2 - Copyright (C) 2004-2010 Internet Systems Consortium, Inc. ("ISC")
3 - Copyright (C) 2000-2003 Internet Software Consortium.
5 - Permission to use, copy, modify, and/or distribute this software for any
6 - purpose with or without fee is hereby granted, provided that the above
7 - copyright notice and this permission notice appear in all copies.
9 - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 - PERFORMANCE OF THIS SOFTWARE.
17 <!-- $Id: Bv9ARM.ch06.html,v 1.201.14.18.2.1 2010/02/25 12:16:44 tbox Exp $ -->
20 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
21 <title>Chapter 6. BIND 9 Configuration Reference</title>
22 <meta name="generator" content="DocBook XSL Stylesheets V1.71.1">
23 <link rel="start" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual">
24 <link rel="up" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual">
25 <link rel="prev" href="Bv9ARM.ch05.html" title="Chapter 5. The BIND 9 Lightweight Resolver">
26 <link rel="next" href="Bv9ARM.ch07.html" title="Chapter 7. BIND 9 Security Considerations">
28 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
29 <div class="navheader">
30 <table width="100%" summary="Navigation header">
31 <tr><th colspan="3" align="center">Chapter 6. <acronym class="acronym">BIND</acronym> 9 Configuration Reference</th></tr>
33 <td width="20%" align="left">
34 <a accesskey="p" href="Bv9ARM.ch05.html">Prev</a> </td>
35 <th width="60%" align="center"> </th>
36 <td width="20%" align="right"> <a accesskey="n" href="Bv9ARM.ch07.html">Next</a>
42 <div class="chapter" lang="en">
43 <div class="titlepage"><div><div><h2 class="title">
44 <a name="Bv9ARM.ch06"></a>Chapter 6. <acronym class="acronym">BIND</acronym> 9 Configuration Reference</h2></div></div></div>
46 <p><b>Table of Contents</b></p>
48 <dt><span class="sect1"><a href="Bv9ARM.ch06.html#configuration_file_elements">Configuration File Elements</a></span></dt>
50 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#address_match_lists">Address Match Lists</a></span></dt>
51 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2573606">Comment Syntax</a></span></dt>
53 <dt><span class="sect1"><a href="Bv9ARM.ch06.html#Configuration_File_Grammar">Configuration File Grammar</a></span></dt>
55 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2574305"><span><strong class="command">acl</strong></span> Statement Grammar</a></span></dt>
56 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#acl"><span><strong class="command">acl</strong></span> Statement Definition and
58 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2574494"><span><strong class="command">controls</strong></span> Statement Grammar</a></span></dt>
59 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#controls_statement_definition_and_usage"><span><strong class="command">controls</strong></span> Statement Definition and
61 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2574923"><span><strong class="command">include</strong></span> Statement Grammar</a></span></dt>
62 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2574940"><span><strong class="command">include</strong></span> Statement Definition and
64 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2574964"><span><strong class="command">key</strong></span> Statement Grammar</a></span></dt>
65 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2574987"><span><strong class="command">key</strong></span> Statement Definition and Usage</a></span></dt>
66 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2575078"><span><strong class="command">logging</strong></span> Statement Grammar</a></span></dt>
67 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2575204"><span><strong class="command">logging</strong></span> Statement Definition and
69 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2577401"><span><strong class="command">lwres</strong></span> Statement Grammar</a></span></dt>
70 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2577475"><span><strong class="command">lwres</strong></span> Statement Definition and Usage</a></span></dt>
71 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2577539"><span><strong class="command">masters</strong></span> Statement Grammar</a></span></dt>
72 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2577582"><span><strong class="command">masters</strong></span> Statement Definition and
74 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2577597"><span><strong class="command">options</strong></span> Statement Grammar</a></span></dt>
75 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#options"><span><strong class="command">options</strong></span> Statement Definition and
77 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#server_statement_grammar"><span><strong class="command">server</strong></span> Statement Grammar</a></span></dt>
78 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#server_statement_definition_and_usage"><span><strong class="command">server</strong></span> Statement Definition and
80 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#statschannels"><span><strong class="command">statistics-channels</strong></span> Statement Grammar</a></span></dt>
81 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2586877"><span><strong class="command">statistics-channels</strong></span> Statement Definition and
83 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2586964"><span><strong class="command">trusted-keys</strong></span> Statement Grammar</a></span></dt>
84 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2587083"><span><strong class="command">trusted-keys</strong></span> Statement Definition
85 and Usage</a></span></dt>
86 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#view_statement_grammar"><span><strong class="command">view</strong></span> Statement Grammar</a></span></dt>
87 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2587165"><span><strong class="command">view</strong></span> Statement Definition and Usage</a></span></dt>
88 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#zone_statement_grammar"><span><strong class="command">zone</strong></span>
89 Statement Grammar</a></span></dt>
90 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2588638"><span><strong class="command">zone</strong></span> Statement Definition and Usage</a></span></dt>
92 <dt><span class="sect1"><a href="Bv9ARM.ch06.html#id2591117">Zone File</a></span></dt>
94 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#types_of_resource_records_and_when_to_use_them">Types of Resource Records and When to Use Them</a></span></dt>
95 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2593348">Discussion of MX Records</a></span></dt>
96 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#Setting_TTLs">Setting TTLs</a></span></dt>
97 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2593895">Inverse Mapping in IPv4</a></span></dt>
98 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2594090">Other Zone File Directives</a></span></dt>
99 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2594500"><acronym class="acronym">BIND</acronym> Master File Extension: the <span><strong class="command">$GENERATE</strong></span> Directive</a></span></dt>
100 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#zonefile_format">Additional File Formats</a></span></dt>
102 <dt><span class="sect1"><a href="Bv9ARM.ch06.html#statistics">BIND9 Statistics</a></span></dt>
103 <dd><dl><dt><span class="sect2"><a href="Bv9ARM.ch06.html#statistics_counters">Statistics Counters</a></span></dt></dl></dd>
107 <acronym class="acronym">BIND</acronym> 9 configuration is broadly similar
108 to <acronym class="acronym">BIND</acronym> 8; however, there are a few new
110 of configuration, such as views. <acronym class="acronym">BIND</acronym>
111 8 configuration files should work with few alterations in <acronym class="acronym">BIND</acronym>
112 9, although more complex configurations should be reviewed to check
113 if they can be more efficiently implemented using the new features
114 found in <acronym class="acronym">BIND</acronym> 9.
117 <acronym class="acronym">BIND</acronym> 4 configuration files can be
118 converted to the new format
119 using the shell script
120 <code class="filename">contrib/named-bootconf/named-bootconf.sh</code>.
122 <div class="sect1" lang="en">
123 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
124 <a name="configuration_file_elements"></a>Configuration File Elements</h2></div></div></div>
126 Following is a list of elements used throughout the <acronym class="acronym">BIND</acronym> configuration
129 <div class="informaltable"><table border="1">
138 <code class="varname">acl_name</code>
143 The name of an <code class="varname">address_match_list</code> as
144 defined by the <span><strong class="command">acl</strong></span> statement.
151 <code class="varname">address_match_list</code>
156 A list of one or more
157 <code class="varname">ip_addr</code>,
158 <code class="varname">ip_prefix</code>, <code class="varname">key_id</code>,
159 or <code class="varname">acl_name</code> elements, see
160 <a href="Bv9ARM.ch06.html#address_match_lists" title="Address Match Lists">the section called “Address Match Lists”</a>.
167 <code class="varname">masters_list</code>
172 A named list of one or more <code class="varname">ip_addr</code>
173 with optional <code class="varname">key_id</code> and/or
174 <code class="varname">ip_port</code>.
175 A <code class="varname">masters_list</code> may include other
176 <code class="varname">masters_lists</code>.
183 <code class="varname">domain_name</code>
188 A quoted string which will be used as
189 a DNS name, for example "<code class="literal">my.test.domain</code>".
196 <code class="varname">dotted_decimal</code>
201 One to four integers valued 0 through
202 255 separated by dots (`.'), such as <span><strong class="command">123</strong></span>,
203 <span><strong class="command">45.67</strong></span> or <span><strong class="command">89.123.45.67</strong></span>.
210 <code class="varname">ip4_addr</code>
215 An IPv4 address with exactly four elements
216 in <code class="varname">dotted_decimal</code> notation.
223 <code class="varname">ip6_addr</code>
228 An IPv6 address, such as <span><strong class="command">2001:db8::1234</strong></span>.
229 IPv6 scoped addresses that have ambiguity on their
230 scope zones must be disambiguated by an appropriate
231 zone ID with the percent character (`%') as
232 delimiter. It is strongly recommended to use
233 string zone names rather than numeric identifiers,
234 in order to be robust against system configuration
235 changes. However, since there is no standard
236 mapping for such names and identifier values,
237 currently only interface names as link identifiers
238 are supported, assuming one-to-one mapping between
239 interfaces and links. For example, a link-local
240 address <span><strong class="command">fe80::1</strong></span> on the link
241 attached to the interface <span><strong class="command">ne0</strong></span>
242 can be specified as <span><strong class="command">fe80::1%ne0</strong></span>.
243 Note that on most systems link-local addresses
244 always have the ambiguity, and need to be
252 <code class="varname">ip_addr</code>
257 An <code class="varname">ip4_addr</code> or <code class="varname">ip6_addr</code>.
264 <code class="varname">ip_port</code>
269 An IP port <code class="varname">number</code>.
270 The <code class="varname">number</code> is limited to 0
271 through 65535, with values
272 below 1024 typically restricted to use by processes running
274 In some cases, an asterisk (`*') character can be used as a
276 select a random high-numbered port.
283 <code class="varname">ip_prefix</code>
288 An IP network specified as an <code class="varname">ip_addr</code>,
289 followed by a slash (`/') and then the number of bits in the
291 Trailing zeros in a <code class="varname">ip_addr</code>
293 For example, <span><strong class="command">127/8</strong></span> is the
294 network <span><strong class="command">127.0.0.0</strong></span> with
295 netmask <span><strong class="command">255.0.0.0</strong></span> and <span><strong class="command">1.2.3.0/28</strong></span> is
296 network <span><strong class="command">1.2.3.0</strong></span> with netmask <span><strong class="command">255.255.255.240</strong></span>.
299 When specifying a prefix involving a IPv6 scoped address
300 the scope may be omitted. In that case the prefix will
301 match packets from any scope.
308 <code class="varname">key_id</code>
313 A <code class="varname">domain_name</code> representing
314 the name of a shared key, to be used for transaction
322 <code class="varname">key_list</code>
327 A list of one or more
328 <code class="varname">key_id</code>s,
329 separated by semicolons and ending with a semicolon.
336 <code class="varname">number</code>
341 A non-negative 32-bit integer
342 (i.e., a number between 0 and 4294967295, inclusive).
343 Its acceptable value might further
344 be limited by the context in which it is used.
351 <code class="varname">path_name</code>
356 A quoted string which will be used as
357 a pathname, such as <code class="filename">zones/master/my.test.domain</code>.
364 <code class="varname">port_list</code>
369 A list of an <code class="varname">ip_port</code> or a port
371 A port range is specified in the form of
372 <strong class="userinput"><code>range</code></strong> followed by
373 two <code class="varname">ip_port</code>s,
374 <code class="varname">port_low</code> and
375 <code class="varname">port_high</code>, which represents
376 port numbers from <code class="varname">port_low</code> through
377 <code class="varname">port_high</code>, inclusive.
378 <code class="varname">port_low</code> must not be larger than
379 <code class="varname">port_high</code>.
381 <strong class="userinput"><code>range 1024 65535</code></strong> represents
382 ports from 1024 through 65535.
383 In either case an asterisk (`*') character is not
384 allowed as a valid <code class="varname">ip_port</code>.
391 <code class="varname">size_spec</code>
396 A number, the word <strong class="userinput"><code>unlimited</code></strong>,
397 or the word <strong class="userinput"><code>default</code></strong>.
400 An <code class="varname">unlimited</code> <code class="varname">size_spec</code> requests unlimited
401 use, or the maximum available amount. A <code class="varname">default size_spec</code> uses
402 the limit that was in force when the server was started.
405 A <code class="varname">number</code> can optionally be
406 followed by a scaling factor:
407 <strong class="userinput"><code>K</code></strong> or <strong class="userinput"><code>k</code></strong>
409 <strong class="userinput"><code>M</code></strong> or <strong class="userinput"><code>m</code></strong>
411 <strong class="userinput"><code>G</code></strong> or <strong class="userinput"><code>g</code></strong> for gigabytes,
412 which scale by 1024, 1024*1024, and 1024*1024*1024
416 The value must be representable as a 64-bit unsigned integer
417 (0 to 18446744073709551615, inclusive).
418 Using <code class="varname">unlimited</code> is the best
420 to safely set a really large number.
427 <code class="varname">yes_or_no</code>
432 Either <strong class="userinput"><code>yes</code></strong> or <strong class="userinput"><code>no</code></strong>.
433 The words <strong class="userinput"><code>true</code></strong> and <strong class="userinput"><code>false</code></strong> are
434 also accepted, as are the numbers <strong class="userinput"><code>1</code></strong>
435 and <strong class="userinput"><code>0</code></strong>.
442 <code class="varname">dialup_option</code>
447 One of <strong class="userinput"><code>yes</code></strong>,
448 <strong class="userinput"><code>no</code></strong>, <strong class="userinput"><code>notify</code></strong>,
449 <strong class="userinput"><code>notify-passive</code></strong>, <strong class="userinput"><code>refresh</code></strong> or
450 <strong class="userinput"><code>passive</code></strong>.
451 When used in a zone, <strong class="userinput"><code>notify-passive</code></strong>,
452 <strong class="userinput"><code>refresh</code></strong>, and <strong class="userinput"><code>passive</code></strong>
453 are restricted to slave and stub zones.
459 <div class="sect2" lang="en">
460 <div class="titlepage"><div><div><h3 class="title">
461 <a name="address_match_lists"></a>Address Match Lists</h3></div></div></div>
462 <div class="sect3" lang="en">
463 <div class="titlepage"><div><div><h4 class="title">
464 <a name="id2573372"></a>Syntax</h4></div></div></div>
465 <pre class="programlisting"><code class="varname">address_match_list</code> = address_match_list_element ;
466 [<span class="optional"> address_match_list_element; ... </span>]
467 <code class="varname">address_match_list_element</code> = [<span class="optional"> ! </span>] (ip_address [<span class="optional">/length</span>] |
468 key key_id | acl_name | { address_match_list } )
471 <div class="sect3" lang="en">
472 <div class="titlepage"><div><div><h4 class="title">
473 <a name="id2573468"></a>Definition and Usage</h4></div></div></div>
475 Address match lists are primarily used to determine access
476 control for various server operations. They are also used in
477 the <span><strong class="command">listen-on</strong></span> and <span><strong class="command">sortlist</strong></span>
478 statements. The elements which constitute an address match
479 list can be any of the following:
481 <div class="itemizedlist"><ul type="disc">
482 <li>an IP address (IPv4 or IPv6)</li>
483 <li>an IP prefix (in `/' notation)</li>
485 a key ID, as defined by the <span><strong class="command">key</strong></span>
488 <li>the name of an address match list defined with
489 the <span><strong class="command">acl</strong></span> statement
491 <li>a nested address match list enclosed in braces</li>
494 Elements can be negated with a leading exclamation mark (`!'),
495 and the match list names "any", "none", "localhost", and
496 "localnets" are predefined. More information on those names
497 can be found in the description of the acl statement.
500 The addition of the key clause made the name of this syntactic
501 element something of a misnomer, since security keys can be used
502 to validate access without regard to a host or network address.
503 Nonetheless, the term "address match list" is still used
504 throughout the documentation.
507 When a given IP address or prefix is compared to an address
508 match list, the comparison takes place in approximately O(1)
509 time. However, key comparisons require that the list of keys
510 be traversed until a matching key is found, and therefore may
514 The interpretation of a match depends on whether the list is being
515 used for access control, defining <span><strong class="command">listen-on</strong></span> ports, or in a
516 <span><strong class="command">sortlist</strong></span>, and whether the element was negated.
519 When used as an access control list, a non-negated match
520 allows access and a negated match denies access. If
521 there is no match, access is denied. The clauses
522 <span><strong class="command">allow-notify</strong></span>,
523 <span><strong class="command">allow-recursion</strong></span>,
524 <span><strong class="command">allow-recursion-on</strong></span>,
525 <span><strong class="command">allow-query</strong></span>,
526 <span><strong class="command">allow-query-on</strong></span>,
527 <span><strong class="command">allow-query-cache</strong></span>,
528 <span><strong class="command">allow-query-cache-on</strong></span>,
529 <span><strong class="command">allow-transfer</strong></span>,
530 <span><strong class="command">allow-update</strong></span>,
531 <span><strong class="command">allow-update-forwarding</strong></span>, and
532 <span><strong class="command">blackhole</strong></span> all use address match
533 lists. Similarly, the <span><strong class="command">listen-on</strong></span> option will cause the
534 server to refuse queries on any of the machine's
535 addresses which do not match the list.
538 Order of insertion is significant. If more than one element
539 in an ACL is found to match a given IP address or prefix,
540 preference will be given to the one that came
541 <span class="emphasis"><em>first</em></span> in the ACL definition.
542 Because of this first-match behavior, an element that
543 defines a subset of another element in the list should
544 come before the broader element, regardless of whether
545 either is negated. For example, in
546 <span><strong class="command">1.2.3/24; ! 1.2.3.13;</strong></span>
547 the 1.2.3.13 element is completely useless because the
548 algorithm will match any lookup for 1.2.3.13 to the 1.2.3/24
549 element. Using <span><strong class="command">! 1.2.3.13; 1.2.3/24</strong></span> fixes
550 that problem by having 1.2.3.13 blocked by the negation, but
551 all other 1.2.3.* hosts fall through.
555 <div class="sect2" lang="en">
556 <div class="titlepage"><div><div><h3 class="title">
557 <a name="id2573606"></a>Comment Syntax</h3></div></div></div>
559 The <acronym class="acronym">BIND</acronym> 9 comment syntax allows for
561 anywhere that whitespace may appear in a <acronym class="acronym">BIND</acronym> configuration
562 file. To appeal to programmers of all kinds, they can be written
563 in the C, C++, or shell/perl style.
565 <div class="sect3" lang="en">
566 <div class="titlepage"><div><div><h4 class="title">
567 <a name="id2573621"></a>Syntax</h4></div></div></div>
570 <pre class="programlisting">/* This is a <acronym class="acronym">BIND</acronym> comment as in C */</pre>
573 <pre class="programlisting">// This is a <acronym class="acronym">BIND</acronym> comment as in C++</pre>
576 <pre class="programlisting"># This is a <acronym class="acronym">BIND</acronym> comment as in common UNIX shells and perl</pre>
580 <div class="sect3" lang="en">
581 <div class="titlepage"><div><div><h4 class="title">
582 <a name="id2573651"></a>Definition and Usage</h4></div></div></div>
584 Comments may appear anywhere that whitespace may appear in
585 a <acronym class="acronym">BIND</acronym> configuration file.
588 C-style comments start with the two characters /* (slash,
589 star) and end with */ (star, slash). Because they are completely
590 delimited with these characters, they can be used to comment only
591 a portion of a line or to span multiple lines.
594 C-style comments cannot be nested. For example, the following
595 is not valid because the entire comment ends with the first */:
600 <pre class="programlisting">/* This is the start of a comment.
601 This is still part of the comment.
602 /* This is an incorrect attempt at nesting a comment. */
603 This is no longer in any comment. */
609 C++-style comments start with the two characters // (slash,
610 slash) and continue to the end of the physical line. They cannot
611 be continued across multiple physical lines; to have one logical
612 comment span multiple lines, each line must use the // pair.
618 <pre class="programlisting">// This is the start of a comment. The next line
619 // is a new comment, even though it is logically
620 // part of the previous comment.
626 Shell-style (or perl-style, if you prefer) comments start
627 with the character <code class="literal">#</code> (number sign)
628 and continue to the end of the
629 physical line, as in C++ comments.
635 <pre class="programlisting"># This is the start of a comment. The next line
636 # is a new comment, even though it is logically
637 # part of the previous comment.
642 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
643 <h3 class="title">Warning</h3>
645 You cannot use the semicolon (`;') character
646 to start a comment such as you would in a zone file. The
647 semicolon indicates the end of a configuration
654 <div class="sect1" lang="en">
655 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
656 <a name="Configuration_File_Grammar"></a>Configuration File Grammar</h2></div></div></div>
658 A <acronym class="acronym">BIND</acronym> 9 configuration consists of
659 statements and comments.
660 Statements end with a semicolon. Statements and comments are the
661 only elements that can appear without enclosing braces. Many
662 statements contain a block of sub-statements, which are also
663 terminated with a semicolon.
666 The following statements are supported:
668 <div class="informaltable"><table border="1">
676 <p><span><strong class="command">acl</strong></span></p>
680 defines a named IP address
681 matching list, for access control and other uses.
687 <p><span><strong class="command">controls</strong></span></p>
691 declares control channels to be used
692 by the <span><strong class="command">rndc</strong></span> utility.
698 <p><span><strong class="command">include</strong></span></p>
708 <p><span><strong class="command">key</strong></span></p>
712 specifies key information for use in
713 authentication and authorization using TSIG.
719 <p><span><strong class="command">logging</strong></span></p>
723 specifies what the server logs, and where
724 the log messages are sent.
730 <p><span><strong class="command">lwres</strong></span></p>
734 configures <span><strong class="command">named</strong></span> to
735 also act as a light-weight resolver daemon (<span><strong class="command">lwresd</strong></span>).
741 <p><span><strong class="command">masters</strong></span></p>
745 defines a named masters list for
746 inclusion in stub and slave zone masters clauses.
752 <p><span><strong class="command">options</strong></span></p>
756 controls global server configuration
757 options and sets defaults for other statements.
763 <p><span><strong class="command">server</strong></span></p>
767 sets certain configuration options on
774 <p><span><strong class="command">statistics-channels</strong></span></p>
778 declares communication channels to get access to
779 <span><strong class="command">named</strong></span> statistics.
785 <p><span><strong class="command">trusted-keys</strong></span></p>
789 defines trusted DNSSEC keys.
795 <p><span><strong class="command">view</strong></span></p>
805 <p><span><strong class="command">zone</strong></span></p>
816 The <span><strong class="command">logging</strong></span> and
817 <span><strong class="command">options</strong></span> statements may only occur once
821 <div class="sect2" lang="en">
822 <div class="titlepage"><div><div><h3 class="title">
823 <a name="id2574305"></a><span><strong class="command">acl</strong></span> Statement Grammar</h3></div></div></div>
824 <pre class="programlisting"><span><strong class="command">acl</strong></span> acl-name {
829 <div class="sect2" lang="en">
830 <div class="titlepage"><div><div><h3 class="title">
831 <a name="acl"></a><span><strong class="command">acl</strong></span> Statement Definition and
832 Usage</h3></div></div></div>
834 The <span><strong class="command">acl</strong></span> statement assigns a symbolic
835 name to an address match list. It gets its name from a primary
836 use of address match lists: Access Control Lists (ACLs).
839 Note that an address match list's name must be defined
840 with <span><strong class="command">acl</strong></span> before it can be used
841 elsewhere; no forward references are allowed.
844 The following ACLs are built-in:
846 <div class="informaltable"><table border="1">
854 <p><span><strong class="command">any</strong></span></p>
864 <p><span><strong class="command">none</strong></span></p>
874 <p><span><strong class="command">localhost</strong></span></p>
878 Matches the IPv4 and IPv6 addresses of all network
879 interfaces on the system.
885 <p><span><strong class="command">localnets</strong></span></p>
889 Matches any host on an IPv4 or IPv6 network
890 for which the system has an interface.
891 Some systems do not provide a way to determine the prefix
893 local IPv6 addresses.
894 In such a case, <span><strong class="command">localnets</strong></span>
895 only matches the local
896 IPv6 addresses, just like <span><strong class="command">localhost</strong></span>.
903 <div class="sect2" lang="en">
904 <div class="titlepage"><div><div><h3 class="title">
905 <a name="id2574494"></a><span><strong class="command">controls</strong></span> Statement Grammar</h3></div></div></div>
906 <pre class="programlisting"><span><strong class="command">controls</strong></span> {
907 [ inet ( ip_addr | * ) [ port ip_port ] allow { <em class="replaceable"><code> address_match_list </code></em> }
908 keys { <em class="replaceable"><code>key_list</code></em> }; ]
910 [ unix <em class="replaceable"><code>path</code></em> perm <em class="replaceable"><code>number</code></em> owner <em class="replaceable"><code>number</code></em> group <em class="replaceable"><code>number</code></em> keys { <em class="replaceable"><code>key_list</code></em> }; ]
915 <div class="sect2" lang="en">
916 <div class="titlepage"><div><div><h3 class="title">
917 <a name="controls_statement_definition_and_usage"></a><span><strong class="command">controls</strong></span> Statement Definition and
918 Usage</h3></div></div></div>
920 The <span><strong class="command">controls</strong></span> statement declares control
921 channels to be used by system administrators to control the
922 operation of the name server. These control channels are
923 used by the <span><strong class="command">rndc</strong></span> utility to send
924 commands to and retrieve non-DNS results from a name server.
927 An <span><strong class="command">inet</strong></span> control channel is a TCP socket
928 listening at the specified <span><strong class="command">ip_port</strong></span> on the
929 specified <span><strong class="command">ip_addr</strong></span>, which can be an IPv4 or IPv6
930 address. An <span><strong class="command">ip_addr</strong></span> of <code class="literal">*</code> (asterisk) is
931 interpreted as the IPv4 wildcard address; connections will be
932 accepted on any of the system's IPv4 addresses.
933 To listen on the IPv6 wildcard address,
934 use an <span><strong class="command">ip_addr</strong></span> of <code class="literal">::</code>.
935 If you will only use <span><strong class="command">rndc</strong></span> on the local host,
936 using the loopback address (<code class="literal">127.0.0.1</code>
937 or <code class="literal">::1</code>) is recommended for maximum security.
940 If no port is specified, port 953 is used. The asterisk
941 "<code class="literal">*</code>" cannot be used for <span><strong class="command">ip_port</strong></span>.
944 The ability to issue commands over the control channel is
945 restricted by the <span><strong class="command">allow</strong></span> and
946 <span><strong class="command">keys</strong></span> clauses.
947 Connections to the control channel are permitted based on the
948 <span><strong class="command">address_match_list</strong></span>. This is for simple
949 IP address based filtering only; any <span><strong class="command">key_id</strong></span>
950 elements of the <span><strong class="command">address_match_list</strong></span>
954 A <span><strong class="command">unix</strong></span> control channel is a UNIX domain
955 socket listening at the specified path in the file system.
956 Access to the socket is specified by the <span><strong class="command">perm</strong></span>,
957 <span><strong class="command">owner</strong></span> and <span><strong class="command">group</strong></span> clauses.
958 Note on some platforms (SunOS and Solaris) the permissions
959 (<span><strong class="command">perm</strong></span>) are applied to the parent directory
960 as the permissions on the socket itself are ignored.
963 The primary authorization mechanism of the command
964 channel is the <span><strong class="command">key_list</strong></span>, which
965 contains a list of <span><strong class="command">key_id</strong></span>s.
966 Each <span><strong class="command">key_id</strong></span> in the <span><strong class="command">key_list</strong></span>
967 is authorized to execute commands over the control channel.
968 See <a href="Bv9ARM.ch03.html#rndc">Remote Name Daemon Control application</a> in <a href="Bv9ARM.ch03.html#admin_tools" title="Administrative Tools">the section called “Administrative Tools”</a>)
969 for information about configuring keys in <span><strong class="command">rndc</strong></span>.
972 If no <span><strong class="command">controls</strong></span> statement is present,
973 <span><strong class="command">named</strong></span> will set up a default
974 control channel listening on the loopback address 127.0.0.1
975 and its IPv6 counterpart ::1.
976 In this case, and also when the <span><strong class="command">controls</strong></span> statement
977 is present but does not have a <span><strong class="command">keys</strong></span> clause,
978 <span><strong class="command">named</strong></span> will attempt to load the command channel key
979 from the file <code class="filename">rndc.key</code> in
980 <code class="filename">/etc</code> (or whatever <code class="varname">sysconfdir</code>
981 was specified as when <acronym class="acronym">BIND</acronym> was built).
982 To create a <code class="filename">rndc.key</code> file, run
983 <strong class="userinput"><code>rndc-confgen -a</code></strong>.
986 The <code class="filename">rndc.key</code> feature was created to
987 ease the transition of systems from <acronym class="acronym">BIND</acronym> 8,
988 which did not have digital signatures on its command channel
989 messages and thus did not have a <span><strong class="command">keys</strong></span> clause.
991 It makes it possible to use an existing <acronym class="acronym">BIND</acronym> 8
992 configuration file in <acronym class="acronym">BIND</acronym> 9 unchanged,
993 and still have <span><strong class="command">rndc</strong></span> work the same way
994 <span><strong class="command">ndc</strong></span> worked in BIND 8, simply by executing the
995 command <strong class="userinput"><code>rndc-confgen -a</code></strong> after BIND 9 is
999 Since the <code class="filename">rndc.key</code> feature
1000 is only intended to allow the backward-compatible usage of
1001 <acronym class="acronym">BIND</acronym> 8 configuration files, this
1003 have a high degree of configurability. You cannot easily change
1004 the key name or the size of the secret, so you should make a
1005 <code class="filename">rndc.conf</code> with your own key if you
1007 those things. The <code class="filename">rndc.key</code> file
1009 permissions set such that only the owner of the file (the user that
1010 <span><strong class="command">named</strong></span> is running as) can access it.
1012 desire greater flexibility in allowing other users to access
1013 <span><strong class="command">rndc</strong></span> commands, then you need to create
1015 <code class="filename">rndc.conf</code> file and make it group
1017 that contains the users who should have access.
1020 To disable the command channel, use an empty
1021 <span><strong class="command">controls</strong></span> statement:
1022 <span><strong class="command">controls { };</strong></span>.
1025 <div class="sect2" lang="en">
1026 <div class="titlepage"><div><div><h3 class="title">
1027 <a name="id2574923"></a><span><strong class="command">include</strong></span> Statement Grammar</h3></div></div></div>
1028 <pre class="programlisting"><span><strong class="command">include</strong></span> <em class="replaceable"><code>filename</code></em>;</pre>
1030 <div class="sect2" lang="en">
1031 <div class="titlepage"><div><div><h3 class="title">
1032 <a name="id2574940"></a><span><strong class="command">include</strong></span> Statement Definition and
1033 Usage</h3></div></div></div>
1035 The <span><strong class="command">include</strong></span> statement inserts the
1036 specified file at the point where the <span><strong class="command">include</strong></span>
1037 statement is encountered. The <span><strong class="command">include</strong></span>
1038 statement facilitates the administration of configuration
1040 by permitting the reading or writing of some things but not
1041 others. For example, the statement could include private keys
1042 that are readable only by the name server.
1045 <div class="sect2" lang="en">
1046 <div class="titlepage"><div><div><h3 class="title">
1047 <a name="id2574964"></a><span><strong class="command">key</strong></span> Statement Grammar</h3></div></div></div>
1048 <pre class="programlisting"><span><strong class="command">key</strong></span> <em class="replaceable"><code>key_id</code></em> {
1049 algorithm <em class="replaceable"><code>string</code></em>;
1050 secret <em class="replaceable"><code>string</code></em>;
1054 <div class="sect2" lang="en">
1055 <div class="titlepage"><div><div><h3 class="title">
1056 <a name="id2574987"></a><span><strong class="command">key</strong></span> Statement Definition and Usage</h3></div></div></div>
1058 The <span><strong class="command">key</strong></span> statement defines a shared
1059 secret key for use with TSIG (see <a href="Bv9ARM.ch04.html#tsig" title="TSIG">the section called “TSIG”</a>)
1060 or the command channel
1061 (see <a href="Bv9ARM.ch06.html#controls_statement_definition_and_usage" title="controls Statement Definition and
1062 Usage">the section called “<span><strong class="command">controls</strong></span> Statement Definition and
1066 The <span><strong class="command">key</strong></span> statement can occur at the
1068 of the configuration file or inside a <span><strong class="command">view</strong></span>
1069 statement. Keys defined in top-level <span><strong class="command">key</strong></span>
1070 statements can be used in all views. Keys intended for use in
1071 a <span><strong class="command">controls</strong></span> statement
1072 (see <a href="Bv9ARM.ch06.html#controls_statement_definition_and_usage" title="controls Statement Definition and
1073 Usage">the section called “<span><strong class="command">controls</strong></span> Statement Definition and
1075 must be defined at the top level.
1078 The <em class="replaceable"><code>key_id</code></em>, also known as the
1079 key name, is a domain name uniquely identifying the key. It can
1080 be used in a <span><strong class="command">server</strong></span>
1081 statement to cause requests sent to that
1082 server to be signed with this key, or in address match lists to
1083 verify that incoming requests have been signed with a key
1084 matching this name, algorithm, and secret.
1087 The <em class="replaceable"><code>algorithm_id</code></em> is a string
1088 that specifies a security/authentication algorithm. Named
1089 supports <code class="literal">hmac-md5</code>,
1090 <code class="literal">hmac-sha1</code>, <code class="literal">hmac-sha224</code>,
1091 <code class="literal">hmac-sha256</code>, <code class="literal">hmac-sha384</code>
1092 and <code class="literal">hmac-sha512</code> TSIG authentication.
1093 Truncated hashes are supported by appending the minimum
1094 number of required bits preceded by a dash, e.g.
1095 <code class="literal">hmac-sha1-80</code>. The
1096 <em class="replaceable"><code>secret_string</code></em> is the secret
1097 to be used by the algorithm, and is treated as a base-64
1101 <div class="sect2" lang="en">
1102 <div class="titlepage"><div><div><h3 class="title">
1103 <a name="id2575078"></a><span><strong class="command">logging</strong></span> Statement Grammar</h3></div></div></div>
1104 <pre class="programlisting"><span><strong class="command">logging</strong></span> {
1105 [ <span><strong class="command">channel</strong></span> <em class="replaceable"><code>channel_name</code></em> {
1106 ( <span><strong class="command">file</strong></span> <em class="replaceable"><code>path_name</code></em>
1107 [ <span><strong class="command">versions</strong></span> ( <em class="replaceable"><code>number</code></em> | <span><strong class="command">unlimited</strong></span> ) ]
1108 [ <span><strong class="command">size</strong></span> <em class="replaceable"><code>size spec</code></em> ]
1109 | <span><strong class="command">syslog</strong></span> <em class="replaceable"><code>syslog_facility</code></em>
1110 | <span><strong class="command">stderr</strong></span>
1111 | <span><strong class="command">null</strong></span> );
1112 [ <span><strong class="command">severity</strong></span> (<code class="option">critical</code> | <code class="option">error</code> | <code class="option">warning</code> | <code class="option">notice</code> |
1113 <code class="option">info</code> | <code class="option">debug</code> [ <em class="replaceable"><code>level</code></em> ] | <code class="option">dynamic</code> ); ]
1114 [ <span><strong class="command">print-category</strong></span> <code class="option">yes</code> or <code class="option">no</code>; ]
1115 [ <span><strong class="command">print-severity</strong></span> <code class="option">yes</code> or <code class="option">no</code>; ]
1116 [ <span><strong class="command">print-time</strong></span> <code class="option">yes</code> or <code class="option">no</code>; ]
1118 [ <span><strong class="command">category</strong></span> <em class="replaceable"><code>category_name</code></em> {
1119 <em class="replaceable"><code>channel_name</code></em> ; [ <em class="replaceable"><code>channel_name</code></em> ; ... ]
1125 <div class="sect2" lang="en">
1126 <div class="titlepage"><div><div><h3 class="title">
1127 <a name="id2575204"></a><span><strong class="command">logging</strong></span> Statement Definition and
1128 Usage</h3></div></div></div>
1130 The <span><strong class="command">logging</strong></span> statement configures a
1132 variety of logging options for the name server. Its <span><strong class="command">channel</strong></span> phrase
1133 associates output methods, format options and severity levels with
1134 a name that can then be used with the <span><strong class="command">category</strong></span> phrase
1135 to select how various classes of messages are logged.
1138 Only one <span><strong class="command">logging</strong></span> statement is used to
1140 as many channels and categories as are wanted. If there is no <span><strong class="command">logging</strong></span> statement,
1141 the logging configuration will be:
1143 <pre class="programlisting">logging {
1144 category default { default_syslog; default_debug; };
1145 category unmatched { null; };
1149 In <acronym class="acronym">BIND</acronym> 9, the logging configuration
1150 is only established when
1151 the entire configuration file has been parsed. In <acronym class="acronym">BIND</acronym> 8, it was
1152 established as soon as the <span><strong class="command">logging</strong></span>
1154 was parsed. When the server is starting up, all logging messages
1155 regarding syntax errors in the configuration file go to the default
1156 channels, or to standard error if the "<code class="option">-g</code>" option
1159 <div class="sect3" lang="en">
1160 <div class="titlepage"><div><div><h4 class="title">
1161 <a name="id2575256"></a>The <span><strong class="command">channel</strong></span> Phrase</h4></div></div></div>
1163 All log output goes to one or more <span class="emphasis"><em>channels</em></span>;
1164 you can make as many of them as you want.
1167 Every channel definition must include a destination clause that
1168 says whether messages selected for the channel go to a file, to a
1169 particular syslog facility, to the standard error stream, or are
1170 discarded. It can optionally also limit the message severity level
1171 that will be accepted by the channel (the default is
1172 <span><strong class="command">info</strong></span>), and whether to include a
1173 <span><strong class="command">named</strong></span>-generated time stamp, the
1175 and/or severity level (the default is not to include any).
1178 The <span><strong class="command">null</strong></span> destination clause
1179 causes all messages sent to the channel to be discarded;
1180 in that case, other options for the channel are meaningless.
1183 The <span><strong class="command">file</strong></span> destination clause directs
1185 to a disk file. It can include limitations
1186 both on how large the file is allowed to become, and how many
1188 of the file will be saved each time the file is opened.
1191 If you use the <span><strong class="command">versions</strong></span> log file
1193 <span><strong class="command">named</strong></span> will retain that many backup
1194 versions of the file by
1195 renaming them when opening. For example, if you choose to keep
1197 of the file <code class="filename">lamers.log</code>, then just
1199 <code class="filename">lamers.log.1</code> is renamed to
1200 <code class="filename">lamers.log.2</code>, <code class="filename">lamers.log.0</code> is renamed
1201 to <code class="filename">lamers.log.1</code>, and <code class="filename">lamers.log</code> is
1202 renamed to <code class="filename">lamers.log.0</code>.
1203 You can say <span><strong class="command">versions unlimited</strong></span> to
1205 the number of versions.
1206 If a <span><strong class="command">size</strong></span> option is associated with
1208 then renaming is only done when the file being opened exceeds the
1209 indicated size. No backup versions are kept by default; any
1211 log file is simply appended.
1214 The <span><strong class="command">size</strong></span> option for files is used
1216 growth. If the file ever exceeds the size, then <span><strong class="command">named</strong></span> will
1217 stop writing to the file unless it has a <span><strong class="command">versions</strong></span> option
1218 associated with it. If backup versions are kept, the files are
1220 described above and a new one begun. If there is no
1221 <span><strong class="command">versions</strong></span> option, no more data will
1222 be written to the log
1223 until some out-of-band mechanism removes or truncates the log to
1225 maximum size. The default behavior is not to limit the size of
1230 Example usage of the <span><strong class="command">size</strong></span> and
1231 <span><strong class="command">versions</strong></span> options:
1233 <pre class="programlisting">channel an_example_channel {
1234 file "example.log" versions 3 size 20m;
1240 The <span><strong class="command">syslog</strong></span> destination clause
1242 channel to the system log. Its argument is a
1243 syslog facility as described in the <span><strong class="command">syslog</strong></span> man
1244 page. Known facilities are <span><strong class="command">kern</strong></span>, <span><strong class="command">user</strong></span>,
1245 <span><strong class="command">mail</strong></span>, <span><strong class="command">daemon</strong></span>, <span><strong class="command">auth</strong></span>,
1246 <span><strong class="command">syslog</strong></span>, <span><strong class="command">lpr</strong></span>, <span><strong class="command">news</strong></span>,
1247 <span><strong class="command">uucp</strong></span>, <span><strong class="command">cron</strong></span>, <span><strong class="command">authpriv</strong></span>,
1248 <span><strong class="command">ftp</strong></span>, <span><strong class="command">local0</strong></span>, <span><strong class="command">local1</strong></span>,
1249 <span><strong class="command">local2</strong></span>, <span><strong class="command">local3</strong></span>, <span><strong class="command">local4</strong></span>,
1250 <span><strong class="command">local5</strong></span>, <span><strong class="command">local6</strong></span> and
1251 <span><strong class="command">local7</strong></span>, however not all facilities
1253 all operating systems.
1254 How <span><strong class="command">syslog</strong></span> will handle messages
1256 this facility is described in the <span><strong class="command">syslog.conf</strong></span> man
1257 page. If you have a system which uses a very old version of <span><strong class="command">syslog</strong></span> that
1258 only uses two arguments to the <span><strong class="command">openlog()</strong></span> function,
1259 then this clause is silently ignored.
1262 The <span><strong class="command">severity</strong></span> clause works like <span><strong class="command">syslog</strong></span>'s
1263 "priorities", except that they can also be used if you are writing
1264 straight to a file rather than using <span><strong class="command">syslog</strong></span>.
1265 Messages which are not at least of the severity level given will
1266 not be selected for the channel; messages of higher severity
1271 If you are using <span><strong class="command">syslog</strong></span>, then the <span><strong class="command">syslog.conf</strong></span> priorities
1272 will also determine what eventually passes through. For example,
1273 defining a channel facility and severity as <span><strong class="command">daemon</strong></span> and <span><strong class="command">debug</strong></span> but
1274 only logging <span><strong class="command">daemon.warning</strong></span> via <span><strong class="command">syslog.conf</strong></span> will
1275 cause messages of severity <span><strong class="command">info</strong></span> and
1276 <span><strong class="command">notice</strong></span> to
1277 be dropped. If the situation were reversed, with <span><strong class="command">named</strong></span> writing
1278 messages of only <span><strong class="command">warning</strong></span> or higher,
1279 then <span><strong class="command">syslogd</strong></span> would
1280 print all messages it received from the channel.
1283 The <span><strong class="command">stderr</strong></span> destination clause
1285 channel to the server's standard error stream. This is intended
1287 use when the server is running as a foreground process, for
1289 when debugging a configuration.
1292 The server can supply extensive debugging information when
1293 it is in debugging mode. If the server's global debug level is
1295 than zero, then debugging mode will be active. The global debug
1296 level is set either by starting the <span><strong class="command">named</strong></span> server
1297 with the <code class="option">-d</code> flag followed by a positive integer,
1298 or by running <span><strong class="command">rndc trace</strong></span>.
1299 The global debug level
1300 can be set to zero, and debugging mode turned off, by running <span><strong class="command">rndc
1301 notrace</strong></span>. All debugging messages in the server have a debug
1302 level, and higher debug levels give more detailed output. Channels
1303 that specify a specific debug severity, for example:
1305 <pre class="programlisting">channel specific_debug_level {
1311 will get debugging output of level 3 or less any time the
1312 server is in debugging mode, regardless of the global debugging
1313 level. Channels with <span><strong class="command">dynamic</strong></span>
1315 server's global debug level to determine what messages to print.
1318 If <span><strong class="command">print-time</strong></span> has been turned on,
1320 the date and time will be logged. <span><strong class="command">print-time</strong></span> may
1321 be specified for a <span><strong class="command">syslog</strong></span> channel,
1323 pointless since <span><strong class="command">syslog</strong></span> also logs
1325 time. If <span><strong class="command">print-category</strong></span> is
1327 category of the message will be logged as well. Finally, if <span><strong class="command">print-severity</strong></span> is
1328 on, then the severity level of the message will be logged. The <span><strong class="command">print-</strong></span> options may
1329 be used in any combination, and will always be printed in the
1331 order: time, category, severity. Here is an example where all
1332 three <span><strong class="command">print-</strong></span> options
1336 <code class="computeroutput">28-Feb-2000 15:05:32.863 general: notice: running</code>
1339 There are four predefined channels that are used for
1340 <span><strong class="command">named</strong></span>'s default logging as follows.
1342 used is described in <a href="Bv9ARM.ch06.html#the_category_phrase" title="The category Phrase">the section called “The <span><strong class="command">category</strong></span> Phrase”</a>.
1344 <pre class="programlisting">channel default_syslog {
1345 syslog daemon; // send to syslog's daemon
1347 severity info; // only send priority info
1351 channel default_debug {
1352 file "named.run"; // write to named.run in
1353 // the working directory
1354 // Note: stderr is used instead
1356 // if the server is started
1357 // with the '-f' option.
1358 severity dynamic; // log at the server's
1359 // current debug level
1362 channel default_stderr {
1363 stderr; // writes to stderr
1364 severity info; // only send priority info
1369 null; // toss anything sent to
1374 The <span><strong class="command">default_debug</strong></span> channel has the
1376 property that it only produces output when the server's debug
1378 nonzero. It normally writes to a file called <code class="filename">named.run</code>
1379 in the server's working directory.
1382 For security reasons, when the "<code class="option">-u</code>"
1383 command line option is used, the <code class="filename">named.run</code> file
1384 is created only after <span><strong class="command">named</strong></span> has
1386 new UID, and any debug output generated while <span><strong class="command">named</strong></span> is
1387 starting up and still running as root is discarded. If you need
1388 to capture this output, you must run the server with the "<code class="option">-g</code>"
1389 option and redirect standard error to a file.
1392 Once a channel is defined, it cannot be redefined. Thus you
1393 cannot alter the built-in channels directly, but you can modify
1394 the default logging by pointing categories at channels you have
1398 <div class="sect3" lang="en">
1399 <div class="titlepage"><div><div><h4 class="title">
1400 <a name="the_category_phrase"></a>The <span><strong class="command">category</strong></span> Phrase</h4></div></div></div>
1402 There are many categories, so you can send the logs you want
1403 to see wherever you want, without seeing logs you don't want. If
1404 you don't specify a list of channels for a category, then log
1406 in that category will be sent to the <span><strong class="command">default</strong></span> category
1407 instead. If you don't specify a default category, the following
1408 "default default" is used:
1410 <pre class="programlisting">category default { default_syslog; default_debug; };
1413 As an example, let's say you want to log security events to
1414 a file, but you also want keep the default logging behavior. You'd
1415 specify the following:
1417 <pre class="programlisting">channel my_security_channel {
1418 file "my_security_file";
1422 my_security_channel;
1427 To discard all messages in a category, specify the <span><strong class="command">null</strong></span> channel:
1429 <pre class="programlisting">category xfer-out { null; };
1430 category notify { null; };
1433 Following are the available categories and brief descriptions
1434 of the types of log information they contain. More
1435 categories may be added in future <acronym class="acronym">BIND</acronym> releases.
1437 <div class="informaltable"><table border="1">
1445 <p><span><strong class="command">default</strong></span></p>
1449 The default category defines the logging
1450 options for those categories where no specific
1451 configuration has been
1458 <p><span><strong class="command">general</strong></span></p>
1462 The catch-all. Many things still aren't
1463 classified into categories, and they all end up here.
1469 <p><span><strong class="command">database</strong></span></p>
1473 Messages relating to the databases used
1474 internally by the name server to store zone and cache
1481 <p><span><strong class="command">security</strong></span></p>
1485 Approval and denial of requests.
1491 <p><span><strong class="command">config</strong></span></p>
1495 Configuration file parsing and processing.
1501 <p><span><strong class="command">resolver</strong></span></p>
1505 DNS resolution, such as the recursive
1506 lookups performed on behalf of clients by a caching name
1513 <p><span><strong class="command">xfer-in</strong></span></p>
1517 Zone transfers the server is receiving.
1523 <p><span><strong class="command">xfer-out</strong></span></p>
1527 Zone transfers the server is sending.
1533 <p><span><strong class="command">notify</strong></span></p>
1537 The NOTIFY protocol.
1543 <p><span><strong class="command">client</strong></span></p>
1547 Processing of client requests.
1553 <p><span><strong class="command">unmatched</strong></span></p>
1557 Messages that <span><strong class="command">named</strong></span> was unable to determine the
1558 class of or for which there was no matching <span><strong class="command">view</strong></span>.
1559 A one line summary is also logged to the <span><strong class="command">client</strong></span> category.
1560 This category is best sent to a file or stderr, by
1561 default it is sent to
1562 the <span><strong class="command">null</strong></span> channel.
1568 <p><span><strong class="command">network</strong></span></p>
1578 <p><span><strong class="command">update</strong></span></p>
1588 <p><span><strong class="command">update-security</strong></span></p>
1592 Approval and denial of update requests.
1598 <p><span><strong class="command">queries</strong></span></p>
1602 Specify where queries should be logged to.
1605 At startup, specifying the category <span><strong class="command">queries</strong></span> will also
1606 enable query logging unless <span><strong class="command">querylog</strong></span> option has been
1611 The query log entry reports the client's IP
1612 address and port number, and the query name,
1613 class and type. It also reports whether the
1614 Recursion Desired flag was set (+ if set, -
1615 if not set), if the query was signed (S),
1616 EDNS was in use (E), if DO (DNSSEC Ok) was
1617 set (D), or if CD (Checking Disabled) was set
1622 <code class="computeroutput">client 127.0.0.1#62536: query: www.example.com IN AAAA +SE</code>
1625 <code class="computeroutput">client ::1#62537: query: www.example.net IN AAAA -SE</code>
1631 <p><span><strong class="command">query-errors</strong></span></p>
1635 Information about queries that resulted in some
1642 <p><span><strong class="command">dispatch</strong></span></p>
1646 Dispatching of incoming packets to the
1647 server modules where they are to be processed.
1653 <p><span><strong class="command">dnssec</strong></span></p>
1657 DNSSEC and TSIG protocol processing.
1663 <p><span><strong class="command">lame-servers</strong></span></p>
1667 Lame servers. These are misconfigurations
1668 in remote servers, discovered by BIND 9 when trying to
1669 query those servers during resolution.
1675 <p><span><strong class="command">delegation-only</strong></span></p>
1679 Delegation only. Logs queries that have been
1680 forced to NXDOMAIN as the result of a
1681 delegation-only zone or a
1682 <span><strong class="command">delegation-only</strong></span> in a hint
1683 or stub zone declaration.
1689 <p><span><strong class="command">edns-disabled</strong></span></p>
1693 Log queries that have been forced to use plain
1694 DNS due to timeouts. This is often due to
1695 the remote servers not being RFC 1034 compliant
1696 (not always returning FORMERR or similar to
1697 EDNS queries and other extensions to the DNS
1698 when they are not understood). In other words, this is
1699 targeted at servers that fail to respond to
1700 DNS queries that they don't understand.
1703 Note: the log message can also be due to
1704 packet loss. Before reporting servers for
1705 non-RFC 1034 compliance they should be re-tested
1706 to determine the nature of the non-compliance.
1707 This testing should prevent or reduce the
1708 number of false-positive reports.
1711 Note: eventually <span><strong class="command">named</strong></span> will have to stop
1712 treating such timeouts as due to RFC 1034 non
1713 compliance and start treating it as plain
1714 packet loss. Falsely classifying packet
1715 loss as due to RFC 1034 non compliance impacts
1716 on DNSSEC validation which requires EDNS for
1717 the DNSSEC records to be returned.
1724 <div class="sect3" lang="en">
1725 <div class="titlepage"><div><div><h4 class="title">
1726 <a name="id2576820"></a>The <span><strong class="command">query-errors</strong></span> Category</h4></div></div></div>
1728 The <span><strong class="command">query-errors</strong></span> category is
1729 specifically intended for debugging purposes: To identify
1730 why and how specific queries result in responses which
1732 Messages of this category are therefore only logged
1733 with <span><strong class="command">debug</strong></span> levels.
1736 At the debug levels of 1 or higher, each response with the
1737 rcode of SERVFAIL is logged as follows:
1740 <code class="computeroutput">client 127.0.0.1#61502: query failed (SERVFAIL) for www.example.com/IN/AAAA at query.c:3880</code>
1743 This means an error resulting in SERVFAIL was
1744 detected at line 3880 of source file
1745 <code class="filename">query.c</code>.
1746 Log messages of this level will particularly
1747 help identify the cause of SERVFAIL for an
1748 authoritative server.
1751 At the debug levels of 2 or higher, detailed context
1752 information of recursive resolutions that resulted in
1754 The log message will look like as follows:
1757 <code class="computeroutput">fetch completed at resolver.c:2970 for www.example.com/A in 30.000183: timed out/success [domain:example.com,referral:2,restart:7,qrysent:8,timeout:5,lame:0,neterr:0,badresp:1,adberr:0,findfail:0,valfail:0]</code>
1760 The first part before the colon shows that a recursive
1761 resolution for AAAA records of www.example.com completed
1762 in 30.000183 seconds and the final result that led to the
1763 SERVFAIL was determined at line 2970 of source file
1764 <code class="filename">resolver.c</code>.
1767 The following part shows the detected final result and the
1768 latest result of DNSSEC validation.
1769 The latter is always success when no validation attempt
1771 In this example, this query resulted in SERVFAIL probably
1772 because all name servers are down or unreachable, leading
1773 to a timeout in 30 seconds.
1774 DNSSEC validation was probably not attempted.
1777 The last part enclosed in square brackets shows statistics
1778 information collected for this particular resolution
1780 The <code class="varname">domain</code> field shows the deepest zone
1781 that the resolver reached;
1782 it is the zone where the error was finally detected.
1783 The meaning of the other fields is summarized in the
1786 <div class="informaltable"><table border="1">
1794 <p><code class="varname">referral</code></p>
1798 The number of referrals the resolver received
1799 throughout the resolution process.
1800 In the above example this is 2, which are most
1801 likely com and example.com.
1807 <p><code class="varname">restart</code></p>
1811 The number of cycles that the resolver tried
1812 remote servers at the <code class="varname">domain</code>
1814 In each cycle the resolver sends one query
1815 (possibly resending it, depending on the response)
1816 to each known name server of
1817 the <code class="varname">domain</code> zone.
1823 <p><code class="varname">qrysent</code></p>
1827 The number of queries the resolver sent at the
1828 <code class="varname">domain</code> zone.
1834 <p><code class="varname">timeout</code></p>
1838 The number of timeouts since the resolver
1839 received the last response.
1845 <p><code class="varname">lame</code></p>
1849 The number of lame servers the resolver detected
1850 at the <code class="varname">domain</code> zone.
1851 A server is detected to be lame either by an
1852 invalid response or as a result of lookup in
1853 BIND9's address database (ADB), where lame
1860 <p><code class="varname">neterr</code></p>
1864 The number of erroneous results that the
1865 resolver encountered in sending queries
1866 at the <code class="varname">domain</code> zone.
1867 One common case is the remote server is
1868 unreachable and the resolver receives an ICMP
1869 unreachable error message.
1875 <p><code class="varname">badresp</code></p>
1879 The number of unexpected responses (other than
1880 <code class="varname">lame</code>) to queries sent by the
1881 resolver at the <code class="varname">domain</code> zone.
1887 <p><code class="varname">adberr</code></p>
1891 Failures in finding remote server addresses
1892 of the <code class="varname">domain</code> zone in the ADB.
1893 One common case of this is that the remote
1894 server's name does not have any address records.
1900 <p><code class="varname">findfail</code></p>
1904 Failures of resolving remote server addresses.
1905 This is a total number of failures throughout
1906 the resolution process.
1912 <p><code class="varname">valfail</code></p>
1916 Failures of DNSSEC validation.
1917 Validation failures are counted throughout
1918 the resolution process (not limited to
1919 the <code class="varname">domain</code> zone), but should
1920 only happen in <code class="varname">domain</code>.
1927 At the debug levels of 3 or higher, the same messages
1928 as those at the debug 1 level are logged for other errors
1930 Note that negative responses such as NXDOMAIN are not
1931 regarded as errors here.
1934 At the debug levels of 4 or higher, the same messages
1935 as those at the debug 2 level are logged for other errors
1937 Unlike the above case of level 3, messages are logged for
1939 This is because any unexpected results can be difficult to
1940 debug in the recursion case.
1944 <div class="sect2" lang="en">
1945 <div class="titlepage"><div><div><h3 class="title">
1946 <a name="id2577401"></a><span><strong class="command">lwres</strong></span> Statement Grammar</h3></div></div></div>
1948 This is the grammar of the <span><strong class="command">lwres</strong></span>
1949 statement in the <code class="filename">named.conf</code> file:
1951 <pre class="programlisting"><span><strong class="command">lwres</strong></span> {
1952 [<span class="optional"> listen-on { <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
1953 [<span class="optional"> view <em class="replaceable"><code>view_name</code></em>; </span>]
1954 [<span class="optional"> search { <em class="replaceable"><code>domain_name</code></em> ; [<span class="optional"> <em class="replaceable"><code>domain_name</code></em> ; ... </span>] }; </span>]
1955 [<span class="optional"> ndots <em class="replaceable"><code>number</code></em>; </span>]
1959 <div class="sect2" lang="en">
1960 <div class="titlepage"><div><div><h3 class="title">
1961 <a name="id2577475"></a><span><strong class="command">lwres</strong></span> Statement Definition and Usage</h3></div></div></div>
1963 The <span><strong class="command">lwres</strong></span> statement configures the
1965 server to also act as a lightweight resolver server. (See
1966 <a href="Bv9ARM.ch05.html#lwresd" title="Running a Resolver Daemon">the section called “Running a Resolver Daemon”</a>.) There may be multiple
1967 <span><strong class="command">lwres</strong></span> statements configuring
1968 lightweight resolver servers with different properties.
1971 The <span><strong class="command">listen-on</strong></span> statement specifies a
1973 addresses (and ports) that this instance of a lightweight resolver
1975 should accept requests on. If no port is specified, port 921 is
1977 If this statement is omitted, requests will be accepted on
1982 The <span><strong class="command">view</strong></span> statement binds this
1984 lightweight resolver daemon to a view in the DNS namespace, so that
1986 response will be constructed in the same manner as a normal DNS
1988 matching this view. If this statement is omitted, the default view
1990 used, and if there is no default view, an error is triggered.
1993 The <span><strong class="command">search</strong></span> statement is equivalent to
1995 <span><strong class="command">search</strong></span> statement in
1996 <code class="filename">/etc/resolv.conf</code>. It provides a
1998 which are appended to relative names in queries.
2001 The <span><strong class="command">ndots</strong></span> statement is equivalent to
2003 <span><strong class="command">ndots</strong></span> statement in
2004 <code class="filename">/etc/resolv.conf</code>. It indicates the
2006 number of dots in a relative domain name that should result in an
2007 exact match lookup before search path elements are appended.
2010 <div class="sect2" lang="en">
2011 <div class="titlepage"><div><div><h3 class="title">
2012 <a name="id2577539"></a><span><strong class="command">masters</strong></span> Statement Grammar</h3></div></div></div>
2013 <pre class="programlisting">
2014 <span><strong class="command">masters</strong></span> <em class="replaceable"><code>name</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] { ( <em class="replaceable"><code>masters_list</code></em> | <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] [<span class="optional">key <em class="replaceable"><code>key</code></em></span>] ) ; [<span class="optional">...</span>] };
2017 <div class="sect2" lang="en">
2018 <div class="titlepage"><div><div><h3 class="title">
2019 <a name="id2577582"></a><span><strong class="command">masters</strong></span> Statement Definition and
2020 Usage</h3></div></div></div>
2021 <p><span><strong class="command">masters</strong></span>
2022 lists allow for a common set of masters to be easily used by
2023 multiple stub and slave zones.
2026 <div class="sect2" lang="en">
2027 <div class="titlepage"><div><div><h3 class="title">
2028 <a name="id2577597"></a><span><strong class="command">options</strong></span> Statement Grammar</h3></div></div></div>
2030 This is the grammar of the <span><strong class="command">options</strong></span>
2031 statement in the <code class="filename">named.conf</code> file:
2033 <pre class="programlisting"><span><strong class="command">options</strong></span> {
2034 [<span class="optional"> version <em class="replaceable"><code>version_string</code></em>; </span>]
2035 [<span class="optional"> hostname <em class="replaceable"><code>hostname_string</code></em>; </span>]
2036 [<span class="optional"> server-id <em class="replaceable"><code>server_id_string</code></em>; </span>]
2037 [<span class="optional"> directory <em class="replaceable"><code>path_name</code></em>; </span>]
2038 [<span class="optional"> key-directory <em class="replaceable"><code>path_name</code></em>; </span>]
2039 [<span class="optional"> named-xfer <em class="replaceable"><code>path_name</code></em>; </span>]
2040 [<span class="optional"> tkey-gssapi-credential <em class="replaceable"><code>principal</code></em>; </span>]
2041 [<span class="optional"> tkey-domain <em class="replaceable"><code>domainname</code></em>; </span>]
2042 [<span class="optional"> tkey-dhkey <em class="replaceable"><code>key_name</code></em> <em class="replaceable"><code>key_tag</code></em>; </span>]
2043 [<span class="optional"> cache-file <em class="replaceable"><code>path_name</code></em>; </span>]
2044 [<span class="optional"> dump-file <em class="replaceable"><code>path_name</code></em>; </span>]
2045 [<span class="optional"> memstatistics <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2046 [<span class="optional"> memstatistics-file <em class="replaceable"><code>path_name</code></em>; </span>]
2047 [<span class="optional"> pid-file <em class="replaceable"><code>path_name</code></em>; </span>]
2048 [<span class="optional"> recursing-file <em class="replaceable"><code>path_name</code></em>; </span>]
2049 [<span class="optional"> statistics-file <em class="replaceable"><code>path_name</code></em>; </span>]
2050 [<span class="optional"> zone-statistics <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2051 [<span class="optional"> auth-nxdomain <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2052 [<span class="optional"> deallocate-on-exit <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2053 [<span class="optional"> dialup <em class="replaceable"><code>dialup_option</code></em>; </span>]
2054 [<span class="optional"> fake-iquery <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2055 [<span class="optional"> fetch-glue <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2056 [<span class="optional"> flush-zones-on-shutdown <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2057 [<span class="optional"> has-old-clients <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2058 [<span class="optional"> host-statistics <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2059 [<span class="optional"> host-statistics-max <em class="replaceable"><code>number</code></em>; </span>]
2060 [<span class="optional"> minimal-responses <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2061 [<span class="optional"> multiple-cnames <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2062 [<span class="optional"> notify <em class="replaceable"><code>yes_or_no</code></em> | <em class="replaceable"><code>explicit</code></em> | <em class="replaceable"><code>master-only</code></em>; </span>]
2063 [<span class="optional"> recursion <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2064 [<span class="optional"> rfc2308-type1 <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2065 [<span class="optional"> use-id-pool <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2066 [<span class="optional"> maintain-ixfr-base <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2067 [<span class="optional"> ixfr-from-differences (<em class="replaceable"><code>yes_or_no</code></em> | <code class="constant">master</code> | <code class="constant">slave</code>); </span>]
2068 [<span class="optional"> dnssec-enable <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2069 [<span class="optional"> dnssec-validation <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2070 [<span class="optional"> dnssec-lookaside <em class="replaceable"><code>domain</code></em> trust-anchor <em class="replaceable"><code>domain</code></em>; </span>]
2071 [<span class="optional"> dnssec-must-be-secure <em class="replaceable"><code>domain yes_or_no</code></em>; </span>]
2072 [<span class="optional"> dnssec-accept-expired <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2073 [<span class="optional"> forward ( <em class="replaceable"><code>only</code></em> | <em class="replaceable"><code>first</code></em> ); </span>]
2074 [<span class="optional"> forwarders { [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
2075 [<span class="optional"> dual-stack-servers [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] {
2076 ( <em class="replaceable"><code>domain_name</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] |
2077 <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ) ;
2079 [<span class="optional"> check-names ( <em class="replaceable"><code>master</code></em> | <em class="replaceable"><code>slave</code></em> | <em class="replaceable"><code>response</code></em> )
2080 ( <em class="replaceable"><code>warn</code></em> | <em class="replaceable"><code>fail</code></em> | <em class="replaceable"><code>ignore</code></em> ); </span>]
2081 [<span class="optional"> check-mx ( <em class="replaceable"><code>warn</code></em> | <em class="replaceable"><code>fail</code></em> | <em class="replaceable"><code>ignore</code></em> ); </span>]
2082 [<span class="optional"> check-wildcard <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2083 [<span class="optional"> check-integrity <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2084 [<span class="optional"> check-mx-cname ( <em class="replaceable"><code>warn</code></em> | <em class="replaceable"><code>fail</code></em> | <em class="replaceable"><code>ignore</code></em> ); </span>]
2085 [<span class="optional"> check-srv-cname ( <em class="replaceable"><code>warn</code></em> | <em class="replaceable"><code>fail</code></em> | <em class="replaceable"><code>ignore</code></em> ); </span>]
2086 [<span class="optional"> check-sibling <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2087 [<span class="optional"> allow-notify { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2088 [<span class="optional"> allow-query { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2089 [<span class="optional"> allow-query-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2090 [<span class="optional"> allow-query-cache { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2091 [<span class="optional"> allow-query-cache-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2092 [<span class="optional"> allow-transfer { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2093 [<span class="optional"> allow-recursion { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2094 [<span class="optional"> allow-recursion-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2095 [<span class="optional"> allow-update { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2096 [<span class="optional"> allow-update-forwarding { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2097 [<span class="optional"> update-check-ksk <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2098 [<span class="optional"> try-tcp-refresh <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2099 [<span class="optional"> allow-v6-synthesis { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2100 [<span class="optional"> blackhole { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2101 [<span class="optional"> use-v4-udp-ports { <em class="replaceable"><code>port_list</code></em> }; </span>]
2102 [<span class="optional"> avoid-v4-udp-ports { <em class="replaceable"><code>port_list</code></em> }; </span>]
2103 [<span class="optional"> use-v6-udp-ports { <em class="replaceable"><code>port_list</code></em> }; </span>]
2104 [<span class="optional"> avoid-v6-udp-ports { <em class="replaceable"><code>port_list</code></em> }; </span>]
2105 [<span class="optional"> listen-on [<span class="optional"> port <em class="replaceable"><code>ip_port</code></em> </span>] { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2106 [<span class="optional"> listen-on-v6 [<span class="optional"> port <em class="replaceable"><code>ip_port</code></em> </span>] { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2107 [<span class="optional"> query-source ( ( <em class="replaceable"><code>ip4_addr</code></em> | <em class="replaceable"><code>*</code></em> )
2108 [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>] |
2109 [<span class="optional"> address ( <em class="replaceable"><code>ip4_addr</code></em> | <em class="replaceable"><code>*</code></em> ) </span>]
2110 [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>] ) ; </span>]
2111 [<span class="optional"> query-source-v6 ( ( <em class="replaceable"><code>ip6_addr</code></em> | <em class="replaceable"><code>*</code></em> )
2112 [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>] |
2113 [<span class="optional"> address ( <em class="replaceable"><code>ip6_addr</code></em> | <em class="replaceable"><code>*</code></em> ) </span>]
2114 [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>] ) ; </span>]
2115 [<span class="optional"> use-queryport-pool <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2116 [<span class="optional"> queryport-pool-ports <em class="replaceable"><code>number</code></em>; </span>]
2117 [<span class="optional"> queryport-pool-updateinterval <em class="replaceable"><code>number</code></em>; </span>]
2118 [<span class="optional"> max-transfer-time-in <em class="replaceable"><code>number</code></em>; </span>]
2119 [<span class="optional"> max-transfer-time-out <em class="replaceable"><code>number</code></em>; </span>]
2120 [<span class="optional"> max-transfer-idle-in <em class="replaceable"><code>number</code></em>; </span>]
2121 [<span class="optional"> max-transfer-idle-out <em class="replaceable"><code>number</code></em>; </span>]
2122 [<span class="optional"> tcp-clients <em class="replaceable"><code>number</code></em>; </span>]
2123 [<span class="optional"> reserved-sockets <em class="replaceable"><code>number</code></em>; </span>]
2124 [<span class="optional"> recursive-clients <em class="replaceable"><code>number</code></em>; </span>]
2125 [<span class="optional"> serial-query-rate <em class="replaceable"><code>number</code></em>; </span>]
2126 [<span class="optional"> serial-queries <em class="replaceable"><code>number</code></em>; </span>]
2127 [<span class="optional"> tcp-listen-queue <em class="replaceable"><code>number</code></em>; </span>]
2128 [<span class="optional"> transfer-format <em class="replaceable"><code>( one-answer | many-answers )</code></em>; </span>]
2129 [<span class="optional"> transfers-in <em class="replaceable"><code>number</code></em>; </span>]
2130 [<span class="optional"> transfers-out <em class="replaceable"><code>number</code></em>; </span>]
2131 [<span class="optional"> transfers-per-ns <em class="replaceable"><code>number</code></em>; </span>]
2132 [<span class="optional"> transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2133 [<span class="optional"> transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2134 [<span class="optional"> alt-transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2135 [<span class="optional"> alt-transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2136 [<span class="optional"> use-alt-transfer-source <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2137 [<span class="optional"> notify-delay <em class="replaceable"><code>seconds</code></em> ; </span>]
2138 [<span class="optional"> notify-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2139 [<span class="optional"> notify-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2140 [<span class="optional"> notify-to-soa <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2141 [<span class="optional"> also-notify { <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
2142 [<span class="optional"> max-ixfr-log-size <em class="replaceable"><code>number</code></em>; </span>]
2143 [<span class="optional"> max-journal-size <em class="replaceable"><code>size_spec</code></em>; </span>]
2144 [<span class="optional"> coresize <em class="replaceable"><code>size_spec</code></em> ; </span>]
2145 [<span class="optional"> datasize <em class="replaceable"><code>size_spec</code></em> ; </span>]
2146 [<span class="optional"> files <em class="replaceable"><code>size_spec</code></em> ; </span>]
2147 [<span class="optional"> stacksize <em class="replaceable"><code>size_spec</code></em> ; </span>]
2148 [<span class="optional"> cleaning-interval <em class="replaceable"><code>number</code></em>; </span>]
2149 [<span class="optional"> heartbeat-interval <em class="replaceable"><code>number</code></em>; </span>]
2150 [<span class="optional"> interface-interval <em class="replaceable"><code>number</code></em>; </span>]
2151 [<span class="optional"> statistics-interval <em class="replaceable"><code>number</code></em>; </span>]
2152 [<span class="optional"> topology { <em class="replaceable"><code>address_match_list</code></em> }</span>];
2153 [<span class="optional"> sortlist { <em class="replaceable"><code>address_match_list</code></em> }</span>];
2154 [<span class="optional"> rrset-order { <em class="replaceable"><code>order_spec</code></em> ; [<span class="optional"> <em class="replaceable"><code>order_spec</code></em> ; ... </span>] </span>] };
2155 [<span class="optional"> lame-ttl <em class="replaceable"><code>number</code></em>; </span>]
2156 [<span class="optional"> max-ncache-ttl <em class="replaceable"><code>number</code></em>; </span>]
2157 [<span class="optional"> max-cache-ttl <em class="replaceable"><code>number</code></em>; </span>]
2158 [<span class="optional"> sig-validity-interval <em class="replaceable"><code>number</code></em> [<span class="optional"><em class="replaceable"><code>number</code></em></span>] ; </span>]
2159 [<span class="optional"> sig-signing-nodes <em class="replaceable"><code>number</code></em> ; </span>]
2160 [<span class="optional"> sig-signing-signatures <em class="replaceable"><code>number</code></em> ; </span>]
2161 [<span class="optional"> sig-signing-type <em class="replaceable"><code>number</code></em> ; </span>]
2162 [<span class="optional"> min-roots <em class="replaceable"><code>number</code></em>; </span>]
2163 [<span class="optional"> use-ixfr <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2164 [<span class="optional"> provide-ixfr <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2165 [<span class="optional"> request-ixfr <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2166 [<span class="optional"> treat-cr-as-space <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2167 [<span class="optional"> min-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
2168 [<span class="optional"> max-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
2169 [<span class="optional"> min-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
2170 [<span class="optional"> max-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
2171 [<span class="optional"> port <em class="replaceable"><code>ip_port</code></em>; </span>]
2172 [<span class="optional"> additional-from-auth <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2173 [<span class="optional"> additional-from-cache <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2174 [<span class="optional"> random-device <em class="replaceable"><code>path_name</code></em> ; </span>]
2175 [<span class="optional"> max-cache-size <em class="replaceable"><code>size_spec</code></em> ; </span>]
2176 [<span class="optional"> match-mapped-addresses <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2177 [<span class="optional"> preferred-glue ( <em class="replaceable"><code>A</code></em> | <em class="replaceable"><code>AAAA</code></em> | <em class="replaceable"><code>NONE</code></em> ); </span>]
2178 [<span class="optional"> edns-udp-size <em class="replaceable"><code>number</code></em>; </span>]
2179 [<span class="optional"> max-udp-size <em class="replaceable"><code>number</code></em>; </span>]
2180 [<span class="optional"> root-delegation-only [<span class="optional"> exclude { <em class="replaceable"><code>namelist</code></em> } </span>] ; </span>]
2181 [<span class="optional"> querylog <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2182 [<span class="optional"> disable-algorithms <em class="replaceable"><code>domain</code></em> { <em class="replaceable"><code>algorithm</code></em>; [<span class="optional"> <em class="replaceable"><code>algorithm</code></em>; </span>] }; </span>]
2183 [<span class="optional"> acache-enable <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2184 [<span class="optional"> acache-cleaning-interval <em class="replaceable"><code>number</code></em>; </span>]
2185 [<span class="optional"> max-acache-size <em class="replaceable"><code>size_spec</code></em> ; </span>]
2186 [<span class="optional"> clients-per-query <em class="replaceable"><code>number</code></em> ; </span>]
2187 [<span class="optional"> max-clients-per-query <em class="replaceable"><code>number</code></em> ; </span>]
2188 [<span class="optional"> masterfile-format (<code class="constant">text</code>|<code class="constant">raw</code>) ; </span>]
2189 [<span class="optional"> empty-server <em class="replaceable"><code>name</code></em> ; </span>]
2190 [<span class="optional"> empty-contact <em class="replaceable"><code>name</code></em> ; </span>]
2191 [<span class="optional"> empty-zones-enable <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2192 [<span class="optional"> disable-empty-zone <em class="replaceable"><code>zone_name</code></em> ; </span>]
2193 [<span class="optional"> zero-no-soa-ttl <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2194 [<span class="optional"> zero-no-soa-ttl-cache <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2198 <div class="sect2" lang="en">
2199 <div class="titlepage"><div><div><h3 class="title">
2200 <a name="options"></a><span><strong class="command">options</strong></span> Statement Definition and
2201 Usage</h3></div></div></div>
2203 The <span><strong class="command">options</strong></span> statement sets up global
2205 to be used by <acronym class="acronym">BIND</acronym>. This statement
2207 once in a configuration file. If there is no <span><strong class="command">options</strong></span>
2208 statement, an options block with each option set to its default will
2211 <div class="variablelist"><dl>
2212 <dt><span class="term"><span><strong class="command">directory</strong></span></span></dt>
2214 The working directory of the server.
2215 Any non-absolute pathnames in the configuration file will be
2217 as relative to this directory. The default location for most
2219 output files (e.g. <code class="filename">named.run</code>)
2221 If a directory is not specified, the working directory
2222 defaults to `<code class="filename">.</code>', the directory from
2224 was started. The directory specified should be an absolute
2227 <dt><span class="term"><span><strong class="command">key-directory</strong></span></span></dt>
2229 When performing dynamic update of secure zones, the
2230 directory where the public and private DNSSEC key files
2231 should be found, if different than the current working
2232 directory. The directory specified must be an absolute
2233 path. (Note that this option has no effect on the paths
2234 for files containing non-DNSSEC keys such as the
2235 <code class="filename">rndc.key</code>.
2237 <dt><span class="term"><span><strong class="command">named-xfer</strong></span></span></dt>
2239 <span class="emphasis"><em>This option is obsolete.</em></span> It
2240 was used in <acronym class="acronym">BIND</acronym> 8 to specify
2241 the pathname to the <span><strong class="command">named-xfer</strong></span>
2242 program. In <acronym class="acronym">BIND</acronym> 9, no separate
2243 <span><strong class="command">named-xfer</strong></span> program is needed;
2244 its functionality is built into the name server.
2246 <dt><span class="term"><span><strong class="command">tkey-gssapi-credential</strong></span></span></dt>
2248 The security credential with which the server should
2249 authenticate keys requested by the GSS-TSIG protocol.
2250 Currently only Kerberos 5 authentication is available
2251 and the credential is a Kerberos principal which
2252 the server can acquire through the default system
2253 key file, normally <code class="filename">/etc/krb5.keytab</code>.
2254 Normally this principal is of the form
2255 "<strong class="userinput"><code>dns/</code></strong><code class="varname">server.domain</code>".
2256 To use GSS-TSIG, <span><strong class="command">tkey-domain</strong></span>
2259 <dt><span class="term"><span><strong class="command">tkey-domain</strong></span></span></dt>
2261 The domain appended to the names of all shared keys
2262 generated with <span><strong class="command">TKEY</strong></span>. When a
2263 client requests a <span><strong class="command">TKEY</strong></span> exchange,
2264 it may or may not specify the desired name for the
2265 key. If present, the name of the shared key will
2266 be <code class="varname">client specified part</code> +
2267 <code class="varname">tkey-domain</code>. Otherwise, the
2268 name of the shared key will be <code class="varname">random hex
2269 digits</code> + <code class="varname">tkey-domain</code>.
2270 In most cases, the <span><strong class="command">domainname</strong></span>
2271 should be the server's domain name, or an otherwise
2272 non-existent subdomain like
2273 "_tkey.<code class="varname">domainname</code>". If you are
2274 using GSS-TSIG, this variable must be defined.
2276 <dt><span class="term"><span><strong class="command">tkey-dhkey</strong></span></span></dt>
2278 The Diffie-Hellman key used by the server
2279 to generate shared keys with clients using the Diffie-Hellman
2281 of <span><strong class="command">TKEY</strong></span>. The server must be
2283 public and private keys from files in the working directory.
2285 most cases, the keyname should be the server's host name.
2287 <dt><span class="term"><span><strong class="command">cache-file</strong></span></span></dt>
2289 This is for testing only. Do not use.
2291 <dt><span class="term"><span><strong class="command">dump-file</strong></span></span></dt>
2293 The pathname of the file the server dumps
2294 the database to when instructed to do so with
2295 <span><strong class="command">rndc dumpdb</strong></span>.
2296 If not specified, the default is <code class="filename">named_dump.db</code>.
2298 <dt><span class="term"><span><strong class="command">memstatistics-file</strong></span></span></dt>
2300 The pathname of the file the server writes memory
2301 usage statistics to on exit. If not specified,
2302 the default is <code class="filename">named.memstats</code>.
2304 <dt><span class="term"><span><strong class="command">pid-file</strong></span></span></dt>
2306 The pathname of the file the server writes its process ID
2307 in. If not specified, the default is
2308 <code class="filename">/var/run/named/named.pid</code>.
2309 The PID file is used by programs that want to send signals to
2311 name server. Specifying <span><strong class="command">pid-file none</strong></span> disables the
2312 use of a PID file — no file will be written and any
2313 existing one will be removed. Note that <span><strong class="command">none</strong></span>
2314 is a keyword, not a filename, and therefore is not enclosed
2318 <dt><span class="term"><span><strong class="command">recursing-file</strong></span></span></dt>
2320 The pathname of the file the server dumps
2321 the queries that are currently recursing when instructed
2322 to do so with <span><strong class="command">rndc recursing</strong></span>.
2323 If not specified, the default is <code class="filename">named.recursing</code>.
2325 <dt><span class="term"><span><strong class="command">statistics-file</strong></span></span></dt>
2327 The pathname of the file the server appends statistics
2328 to when instructed to do so using <span><strong class="command">rndc stats</strong></span>.
2329 If not specified, the default is <code class="filename">named.stats</code> in the
2330 server's current directory. The format of the file is
2332 in <a href="Bv9ARM.ch06.html#statsfile" title="The Statistics File">the section called “The Statistics File”</a>.
2334 <dt><span class="term"><span><strong class="command">port</strong></span></span></dt>
2336 The UDP/TCP port number the server uses for
2337 receiving and sending DNS protocol traffic.
2338 The default is 53. This option is mainly intended for server
2340 a server using a port other than 53 will not be able to
2344 <dt><span class="term"><span><strong class="command">random-device</strong></span></span></dt>
2346 The source of entropy to be used by the server. Entropy is
2348 for DNSSEC operations, such as TKEY transactions and dynamic
2350 zones. This options specifies the device (or file) from which
2352 entropy. If this is a file, operations requiring entropy will
2354 file has been exhausted. If not specified, the default value
2356 <code class="filename">/dev/random</code>
2357 (or equivalent) when present, and none otherwise. The
2358 <span><strong class="command">random-device</strong></span> option takes
2360 the initial configuration load at server startup time and
2361 is ignored on subsequent reloads.
2363 <dt><span class="term"><span><strong class="command">preferred-glue</strong></span></span></dt>
2365 If specified, the listed type (A or AAAA) will be emitted
2367 in the additional section of a query response.
2368 The default is not to prefer any type (NONE).
2371 <a name="root_delegation_only"></a><span class="term"><span><strong class="command">root-delegation-only</strong></span></span>
2375 Turn on enforcement of delegation-only in TLDs
2376 (top level domains) and root zones with an optional
2380 DS queries are expected to be made to and be answered by
2381 delegation only zones. Such queries and responses are
2382 treated as a exception to delegation-only processing
2383 and are not converted to NXDOMAIN responses provided
2384 a CNAME is not discovered at the query name.
2387 If a delegation only zone server also serves a child
2388 zone it is not always possible to determine whether
2389 a answer comes from the delegation only zone or the
2390 child zone. SOA NS and DNSKEY records are apex
2391 only records and a matching response that contains
2392 these records or DS is treated as coming from a
2393 child zone. RRSIG records are also examined to see
2394 if they are signed by a child zone or not. The
2395 authority section is also examined to see if there
2396 is evidence that the answer is from the child zone.
2397 Answers that are determined to be from a child zone
2398 are not converted to NXDOMAIN responses. Despite
2399 all these checks there is still a possibility of
2400 false negatives when a child zone is being served.
2403 Similarly false positives can arise from empty nodes
2404 (no records at the name) in the delegation only zone
2405 when the query type is not ANY.
2408 Note some TLDs are not delegation only (e.g. "DE", "LV",
2409 "US" and "MUSEUM"). This list is not exhaustive.
2411 <pre class="programlisting">
2413 root-delegation-only exclude { "de"; "lv"; "us"; "museum"; };
2417 <dt><span class="term"><span><strong class="command">disable-algorithms</strong></span></span></dt>
2419 Disable the specified DNSSEC algorithms at and below the
2421 Multiple <span><strong class="command">disable-algorithms</strong></span>
2422 statements are allowed.
2423 Only the most specific will be applied.
2425 <dt><span class="term"><span><strong class="command">dnssec-lookaside</strong></span></span></dt>
2427 When set, <span><strong class="command">dnssec-lookaside</strong></span>
2429 validator with an alternate method to validate DNSKEY records
2431 top of a zone. When a DNSKEY is at or below a domain
2433 deepest <span><strong class="command">dnssec-lookaside</strong></span>, and
2434 the normal DNSSEC validation
2435 has left the key untrusted, the trust-anchor will be append to
2437 name and a DLV record will be looked up to see if it can
2439 key. If the DLV record validates a DNSKEY (similarly to the
2441 record does) the DNSKEY RRset is deemed to be trusted.
2443 <dt><span class="term"><span><strong class="command">dnssec-must-be-secure</strong></span></span></dt>
2445 Specify hierarchies which must be or may not be secure (signed and
2447 If <strong class="userinput"><code>yes</code></strong>, then <span><strong class="command">named</strong></span> will only accept
2450 If <strong class="userinput"><code>no</code></strong>, then normal DNSSEC validation
2452 allowing for insecure answers to be accepted.
2453 The specified domain must be under a <span><strong class="command">trusted-key</strong></span> or
2454 <span><strong class="command">dnssec-lookaside</strong></span> must be
2458 <div class="sect3" lang="en">
2459 <div class="titlepage"><div><div><h4 class="title">
2460 <a name="boolean_options"></a>Boolean Options</h4></div></div></div>
2461 <div class="variablelist"><dl>
2462 <dt><span class="term"><span><strong class="command">auth-nxdomain</strong></span></span></dt>
2464 If <strong class="userinput"><code>yes</code></strong>, then the <span><strong class="command">AA</strong></span> bit
2465 is always set on NXDOMAIN responses, even if the server is
2467 authoritative. The default is <strong class="userinput"><code>no</code></strong>;
2469 a change from <acronym class="acronym">BIND</acronym> 8. If you
2470 are using very old DNS software, you
2471 may need to set it to <strong class="userinput"><code>yes</code></strong>.
2473 <dt><span class="term"><span><strong class="command">deallocate-on-exit</strong></span></span></dt>
2475 This option was used in <acronym class="acronym">BIND</acronym>
2476 8 to enable checking
2477 for memory leaks on exit. <acronym class="acronym">BIND</acronym> 9 ignores the option and always performs
2480 <dt><span class="term"><span><strong class="command">memstatistics</strong></span></span></dt>
2482 Write memory statistics to the file specified by
2483 <span><strong class="command">memstatistics-file</strong></span> at exit.
2484 The default is <strong class="userinput"><code>no</code></strong> unless
2485 '-m record' is specified on the command line in
2486 which case it is <strong class="userinput"><code>yes</code></strong>.
2488 <dt><span class="term"><span><strong class="command">dialup</strong></span></span></dt>
2491 If <strong class="userinput"><code>yes</code></strong>, then the
2492 server treats all zones as if they are doing zone transfers
2494 a dial-on-demand dialup link, which can be brought up by
2496 originating from this server. This has different effects
2498 to zone type and concentrates the zone maintenance so that
2500 happens in a short interval, once every <span><strong class="command">heartbeat-interval</strong></span> and
2501 hopefully during the one call. It also suppresses some of
2503 zone maintenance traffic. The default is <strong class="userinput"><code>no</code></strong>.
2506 The <span><strong class="command">dialup</strong></span> option
2507 may also be specified in the <span><strong class="command">view</strong></span> and
2508 <span><strong class="command">zone</strong></span> statements,
2509 in which case it overrides the global <span><strong class="command">dialup</strong></span>
2513 If the zone is a master zone, then the server will send out a
2515 request to all the slaves (default). This should trigger the
2517 number check in the slave (providing it supports NOTIFY)
2519 to verify the zone while the connection is active.
2520 The set of servers to which NOTIFY is sent can be controlled
2522 <span><strong class="command">notify</strong></span> and <span><strong class="command">also-notify</strong></span>.
2526 zone is a slave or stub zone, then the server will suppress
2528 "zone up to date" (refresh) queries and only perform them
2530 <span><strong class="command">heartbeat-interval</strong></span> expires in
2535 Finer control can be achieved by using
2536 <strong class="userinput"><code>notify</code></strong> which only sends NOTIFY
2538 <strong class="userinput"><code>notify-passive</code></strong> which sends NOTIFY
2540 suppresses the normal refresh queries, <strong class="userinput"><code>refresh</code></strong>
2541 which suppresses normal refresh processing and sends refresh
2543 when the <span><strong class="command">heartbeat-interval</strong></span>
2545 <strong class="userinput"><code>passive</code></strong> which just disables normal
2549 <div class="informaltable"><table border="1">
2581 <p><span><strong class="command">no</strong></span> (default)</p>
2601 <p><span><strong class="command">yes</strong></span></p>
2621 <p><span><strong class="command">notify</strong></span></p>
2641 <p><span><strong class="command">refresh</strong></span></p>
2661 <p><span><strong class="command">passive</strong></span></p>
2681 <p><span><strong class="command">notify-passive</strong></span></p>
2702 Note that normal NOTIFY processing is not affected by
2703 <span><strong class="command">dialup</strong></span>.
2706 <dt><span class="term"><span><strong class="command">fake-iquery</strong></span></span></dt>
2708 In <acronym class="acronym">BIND</acronym> 8, this option
2709 enabled simulating the obsolete DNS query type
2710 IQUERY. <acronym class="acronym">BIND</acronym> 9 never does
2713 <dt><span class="term"><span><strong class="command">fetch-glue</strong></span></span></dt>
2715 This option is obsolete.
2716 In BIND 8, <strong class="userinput"><code>fetch-glue yes</code></strong>
2717 caused the server to attempt to fetch glue resource records
2719 didn't have when constructing the additional
2720 data section of a response. This is now considered a bad
2722 and BIND 9 never does it.
2724 <dt><span class="term"><span><strong class="command">flush-zones-on-shutdown</strong></span></span></dt>
2726 When the nameserver exits due receiving SIGTERM,
2727 flush or do not flush any pending zone writes. The default
2729 <span><strong class="command">flush-zones-on-shutdown</strong></span> <strong class="userinput"><code>no</code></strong>.
2731 <dt><span class="term"><span><strong class="command">has-old-clients</strong></span></span></dt>
2733 This option was incorrectly implemented
2734 in <acronym class="acronym">BIND</acronym> 8, and is ignored by <acronym class="acronym">BIND</acronym> 9.
2735 To achieve the intended effect
2737 <span><strong class="command">has-old-clients</strong></span> <strong class="userinput"><code>yes</code></strong>, specify
2738 the two separate options <span><strong class="command">auth-nxdomain</strong></span> <strong class="userinput"><code>yes</code></strong>
2739 and <span><strong class="command">rfc2308-type1</strong></span> <strong class="userinput"><code>no</code></strong> instead.
2741 <dt><span class="term"><span><strong class="command">host-statistics</strong></span></span></dt>
2743 In BIND 8, this enables keeping of
2744 statistics for every host that the name server interacts
2746 Not implemented in BIND 9.
2748 <dt><span class="term"><span><strong class="command">maintain-ixfr-base</strong></span></span></dt>
2750 <span class="emphasis"><em>This option is obsolete</em></span>.
2751 It was used in <acronym class="acronym">BIND</acronym> 8 to
2752 determine whether a transaction log was
2753 kept for Incremental Zone Transfer. <acronym class="acronym">BIND</acronym> 9 maintains a transaction
2754 log whenever possible. If you need to disable outgoing
2756 transfers, use <span><strong class="command">provide-ixfr</strong></span> <strong class="userinput"><code>no</code></strong>.
2758 <dt><span class="term"><span><strong class="command">minimal-responses</strong></span></span></dt>
2760 If <strong class="userinput"><code>yes</code></strong>, then when generating
2761 responses the server will only add records to the authority
2762 and additional data sections when they are required (e.g.
2763 delegations, negative responses). This may improve the
2764 performance of the server.
2765 The default is <strong class="userinput"><code>no</code></strong>.
2767 <dt><span class="term"><span><strong class="command">multiple-cnames</strong></span></span></dt>
2769 This option was used in <acronym class="acronym">BIND</acronym> 8 to allow
2770 a domain name to have multiple CNAME records in violation of
2771 the DNS standards. <acronym class="acronym">BIND</acronym> 9.2 onwards
2772 always strictly enforces the CNAME rules both in master
2773 files and dynamic updates.
2775 <dt><span class="term"><span><strong class="command">notify</strong></span></span></dt>
2778 If <strong class="userinput"><code>yes</code></strong> (the default),
2779 DNS NOTIFY messages are sent when a zone the server is
2781 changes, see <a href="Bv9ARM.ch04.html#notify" title="Notify">the section called “Notify”</a>. The messages are
2783 servers listed in the zone's NS records (except the master
2785 in the SOA MNAME field), and to any servers listed in the
2786 <span><strong class="command">also-notify</strong></span> option.
2789 If <strong class="userinput"><code>master-only</code></strong>, notifies are only
2792 If <strong class="userinput"><code>explicit</code></strong>, notifies are sent only
2794 servers explicitly listed using <span><strong class="command">also-notify</strong></span>.
2795 If <strong class="userinput"><code>no</code></strong>, no notifies are sent.
2798 The <span><strong class="command">notify</strong></span> option may also be
2799 specified in the <span><strong class="command">zone</strong></span>
2801 in which case it overrides the <span><strong class="command">options notify</strong></span> statement.
2802 It would only be necessary to turn off this option if it
2807 <dt><span class="term"><span><strong class="command">notify-to-soa</strong></span></span></dt>
2809 If <strong class="userinput"><code>yes</code></strong> do not check the nameservers
2810 in the NS RRset against the SOA MNAME. Normally a NOTIFY
2811 message is not sent to the SOA MNAME (SOA ORIGIN) as it is
2812 supposed to contain the name of the ultimate master.
2813 Sometimes, however, a slave is listed as the SOA MNAME in
2814 hidden master configurations and in that case you would
2815 want the ultimate master to still send NOTIFY messages to
2816 all the nameservers listed in the NS RRset.
2818 <dt><span class="term"><span><strong class="command">recursion</strong></span></span></dt>
2820 If <strong class="userinput"><code>yes</code></strong>, and a
2821 DNS query requests recursion, then the server will attempt
2823 all the work required to answer the query. If recursion is
2825 and the server does not already know the answer, it will
2827 referral response. The default is
2828 <strong class="userinput"><code>yes</code></strong>.
2829 Note that setting <span><strong class="command">recursion no</strong></span> does not prevent
2830 clients from getting data from the server's cache; it only
2831 prevents new data from being cached as an effect of client
2833 Caching may still occur as an effect the server's internal
2834 operation, such as NOTIFY address lookups.
2835 See also <span><strong class="command">fetch-glue</strong></span> above.
2837 <dt><span class="term"><span><strong class="command">rfc2308-type1</strong></span></span></dt>
2840 Setting this to <strong class="userinput"><code>yes</code></strong> will
2841 cause the server to send NS records along with the SOA
2843 answers. The default is <strong class="userinput"><code>no</code></strong>.
2845 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
2846 <h3 class="title">Note</h3>
2848 Not yet implemented in <acronym class="acronym">BIND</acronym>
2853 <dt><span class="term"><span><strong class="command">use-id-pool</strong></span></span></dt>
2855 <span class="emphasis"><em>This option is obsolete</em></span>.
2856 <acronym class="acronym">BIND</acronym> 9 always allocates query
2859 <dt><span class="term"><span><strong class="command">zone-statistics</strong></span></span></dt>
2861 If <strong class="userinput"><code>yes</code></strong>, the server will collect
2862 statistical data on all zones (unless specifically turned
2864 on a per-zone basis by specifying <span><strong class="command">zone-statistics no</strong></span>
2865 in the <span><strong class="command">zone</strong></span> statement).
2866 These statistics may be accessed
2867 using <span><strong class="command">rndc stats</strong></span>, which will
2868 dump them to the file listed
2869 in the <span><strong class="command">statistics-file</strong></span>. See
2870 also <a href="Bv9ARM.ch06.html#statsfile" title="The Statistics File">the section called “The Statistics File”</a>.
2872 <dt><span class="term"><span><strong class="command">use-ixfr</strong></span></span></dt>
2874 <span class="emphasis"><em>This option is obsolete</em></span>.
2875 If you need to disable IXFR to a particular server or
2877 the information on the <span><strong class="command">provide-ixfr</strong></span> option
2878 in <a href="Bv9ARM.ch06.html#server_statement_definition_and_usage" title="server Statement Definition and
2879 Usage">the section called “<span><strong class="command">server</strong></span> Statement Definition and
2882 <a href="Bv9ARM.ch04.html#incremental_zone_transfers" title="Incremental Zone Transfers (IXFR)">the section called “Incremental Zone Transfers (IXFR)”</a>.
2884 <dt><span class="term"><span><strong class="command">provide-ixfr</strong></span></span></dt>
2886 See the description of
2887 <span><strong class="command">provide-ixfr</strong></span> in
2888 <a href="Bv9ARM.ch06.html#server_statement_definition_and_usage" title="server Statement Definition and
2889 Usage">the section called “<span><strong class="command">server</strong></span> Statement Definition and
2892 <dt><span class="term"><span><strong class="command">request-ixfr</strong></span></span></dt>
2894 See the description of
2895 <span><strong class="command">request-ixfr</strong></span> in
2896 <a href="Bv9ARM.ch06.html#server_statement_definition_and_usage" title="server Statement Definition and
2897 Usage">the section called “<span><strong class="command">server</strong></span> Statement Definition and
2900 <dt><span class="term"><span><strong class="command">treat-cr-as-space</strong></span></span></dt>
2902 This option was used in <acronym class="acronym">BIND</acronym>
2904 the server treat carriage return ("<span><strong class="command">\r</strong></span>") characters the same way
2905 as a space or tab character,
2906 to facilitate loading of zone files on a UNIX system that
2908 on an NT or DOS machine. In <acronym class="acronym">BIND</acronym> 9, both UNIX "<span><strong class="command">\n</strong></span>"
2909 and NT/DOS "<span><strong class="command">\r\n</strong></span>" newlines
2910 are always accepted,
2911 and the option is ignored.
2914 <span class="term"><span><strong class="command">additional-from-auth</strong></span>, </span><span class="term"><span><strong class="command">additional-from-cache</strong></span></span>
2918 These options control the behavior of an authoritative
2920 answering queries which have additional data, or when
2925 When both of these options are set to <strong class="userinput"><code>yes</code></strong>
2927 query is being answered from authoritative data (a zone
2928 configured into the server), the additional data section of
2930 reply will be filled in using data from other authoritative
2932 and from the cache. In some situations this is undesirable,
2934 as when there is concern over the correctness of the cache,
2936 in servers where slave zones may be added and modified by
2937 untrusted third parties. Also, avoiding
2938 the search for this additional data will speed up server
2940 at the possible expense of additional queries to resolve
2942 otherwise be provided in the additional section.
2945 For example, if a query asks for an MX record for host <code class="literal">foo.example.com</code>,
2946 and the record found is "<code class="literal">MX 10 mail.example.net</code>", normally the address
2947 records (A and AAAA) for <code class="literal">mail.example.net</code> will be provided as well,
2948 if known, even though they are not in the example.com zone.
2949 Setting these options to <span><strong class="command">no</strong></span>
2950 disables this behavior and makes
2951 the server only search for additional data in the zone it
2955 These options are intended for use in authoritative-only
2956 servers, or in authoritative-only views. Attempts to set
2957 them to <span><strong class="command">no</strong></span> without also
2959 <span><strong class="command">recursion no</strong></span> will cause the
2961 ignore the options and log a warning message.
2964 Specifying <span><strong class="command">additional-from-cache no</strong></span> actually
2965 disables the use of the cache not only for additional data
2967 but also when looking up the answer. This is usually the
2969 behavior in an authoritative-only server where the
2971 the cached data is an issue.
2974 When a name server is non-recursively queried for a name
2976 below the apex of any served zone, it normally answers with
2978 "upwards referral" to the root servers or the servers of
2980 known parent of the query name. Since the data in an
2982 comes from the cache, the server will not be able to provide
2984 referrals when <span><strong class="command">additional-from-cache no</strong></span>
2985 has been specified. Instead, it will respond to such
2987 with REFUSED. This should not cause any problems since
2988 upwards referrals are not required for the resolution
2992 <dt><span class="term"><span><strong class="command">match-mapped-addresses</strong></span></span></dt>
2995 If <strong class="userinput"><code>yes</code></strong>, then an
2996 IPv4-mapped IPv6 address will match any address match
2997 list entries that match the corresponding IPv4 address.
3000 This option was introduced to work around a kernel quirk
3001 in some operating systems that causes IPv4 TCP
3002 connections, such as zone transfers, to be accepted on an
3003 IPv6 socket using mapped addresses. This caused address
3004 match lists designed for IPv4 to fail to match. However,
3005 <span><strong class="command">named</strong></span> now solves this problem
3006 internally. The use of this option is discouraged.
3009 <dt><span class="term"><span><strong class="command">ixfr-from-differences</strong></span></span></dt>
3012 When <strong class="userinput"><code>yes</code></strong> and the server loads a new version of a master
3013 zone from its zone file or receives a new version of a slave
3014 file by a non-incremental zone transfer, it will compare
3015 the new version to the previous one and calculate a set
3016 of differences. The differences are then logged in the
3017 zone's journal file such that the changes can be transmitted
3018 to downstream slaves as an incremental zone transfer.
3021 By allowing incremental zone transfers to be used for
3022 non-dynamic zones, this option saves bandwidth at the
3023 expense of increased CPU and memory consumption at the
3025 In particular, if the new version of a zone is completely
3026 different from the previous one, the set of differences
3027 will be of a size comparable to the combined size of the
3028 old and new zone version, and the server will need to
3029 temporarily allocate memory to hold this complete
3032 <p><span><strong class="command">ixfr-from-differences</strong></span>
3033 also accepts <span><strong class="command">master</strong></span> and
3034 <span><strong class="command">slave</strong></span> at the view and options
3036 <span><strong class="command">ixfr-from-differences</strong></span> to be enabled for
3037 all <span><strong class="command">master</strong></span> or
3038 <span><strong class="command">slave</strong></span> zones respectively.
3039 It is off by default.
3042 <dt><span class="term"><span><strong class="command">multi-master</strong></span></span></dt>
3044 This should be set when you have multiple masters for a zone
3046 addresses refer to different machines. If <strong class="userinput"><code>yes</code></strong>, <span><strong class="command">named</strong></span> will
3048 when the serial number on the master is less than what <span><strong class="command">named</strong></span>
3050 has. The default is <strong class="userinput"><code>no</code></strong>.
3052 <dt><span class="term"><span><strong class="command">dnssec-enable</strong></span></span></dt>
3054 Enable DNSSEC support in <span><strong class="command">named</strong></span>. Unless set to <strong class="userinput"><code>yes</code></strong>,
3055 <span><strong class="command">named</strong></span> behaves as if it does not support DNSSEC.
3056 The default is <strong class="userinput"><code>yes</code></strong>.
3058 <dt><span class="term"><span><strong class="command">dnssec-validation</strong></span></span></dt>
3060 Enable DNSSEC validation in <span><strong class="command">named</strong></span>.
3061 Note <span><strong class="command">dnssec-enable</strong></span> also needs to be
3062 set to <strong class="userinput"><code>yes</code></strong> to be effective.
3063 The default is <strong class="userinput"><code>yes</code></strong>.
3065 <dt><span class="term"><span><strong class="command">dnssec-accept-expired</strong></span></span></dt>
3067 Accept expired signatures when verifying DNSSEC signatures.
3068 The default is <strong class="userinput"><code>no</code></strong>.
3069 Setting this option to "yes" leaves <span><strong class="command">named</strong></span> vulnerable to replay attacks.
3071 <dt><span class="term"><span><strong class="command">querylog</strong></span></span></dt>
3073 Specify whether query logging should be started when <span><strong class="command">named</strong></span>
3075 If <span><strong class="command">querylog</strong></span> is not specified,
3076 then the query logging
3077 is determined by the presence of the logging category <span><strong class="command">queries</strong></span>.
3079 <dt><span class="term"><span><strong class="command">check-names</strong></span></span></dt>
3082 This option is used to restrict the character set and syntax
3084 certain domain names in master files and/or DNS responses
3086 from the network. The default varies according to usage
3088 <span><strong class="command">master</strong></span> zones the default is <span><strong class="command">fail</strong></span>.
3089 For <span><strong class="command">slave</strong></span> zones the default
3090 is <span><strong class="command">warn</strong></span>.
3091 For answers received from the network (<span><strong class="command">response</strong></span>)
3092 the default is <span><strong class="command">ignore</strong></span>.
3095 The rules for legal hostnames and mail domains are derived
3096 from RFC 952 and RFC 821 as modified by RFC 1123.
3098 <p><span><strong class="command">check-names</strong></span>
3099 applies to the owner names of A, AAAA and MX records.
3100 It also applies to the domain names in the RDATA of NS, SOA,
3101 MX, and SRV records.
3102 It also applies to the RDATA of PTR records where the owner
3103 name indicated that it is a reverse lookup of a hostname
3104 (the owner name ends in IN-ADDR.ARPA, IP6.ARPA, or IP6.INT).
3107 <dt><span class="term"><span><strong class="command">check-mx</strong></span></span></dt>
3109 Check whether the MX record appears to refer to a IP address.
3110 The default is to <span><strong class="command">warn</strong></span>. Other possible
3111 values are <span><strong class="command">fail</strong></span> and
3112 <span><strong class="command">ignore</strong></span>.
3114 <dt><span class="term"><span><strong class="command">check-wildcard</strong></span></span></dt>
3116 This option is used to check for non-terminal wildcards.
3117 The use of non-terminal wildcards is almost always as a
3119 to understand the wildcard matching algorithm (RFC 1034).
3121 affects master zones. The default (<span><strong class="command">yes</strong></span>) is to check
3122 for non-terminal wildcards and issue a warning.
3124 <dt><span class="term"><span><strong class="command">check-integrity</strong></span></span></dt>
3126 Perform post load zone integrity checks on master
3127 zones. This checks that MX and SRV records refer
3128 to address (A or AAAA) records and that glue
3129 address records exist for delegated zones. For
3130 MX and SRV records only in-zone hostnames are
3131 checked (for out-of-zone hostnames use
3132 <span><strong class="command">named-checkzone</strong></span>).
3133 For NS records only names below top of zone are
3134 checked (for out-of-zone names and glue consistency
3135 checks use <span><strong class="command">named-checkzone</strong></span>).
3136 The default is <span><strong class="command">yes</strong></span>.
3138 <dt><span class="term"><span><strong class="command">check-mx-cname</strong></span></span></dt>
3140 If <span><strong class="command">check-integrity</strong></span> is set then
3141 fail, warn or ignore MX records that refer
3142 to CNAMES. The default is to <span><strong class="command">warn</strong></span>.
3144 <dt><span class="term"><span><strong class="command">check-srv-cname</strong></span></span></dt>
3146 If <span><strong class="command">check-integrity</strong></span> is set then
3147 fail, warn or ignore SRV records that refer
3148 to CNAMES. The default is to <span><strong class="command">warn</strong></span>.
3150 <dt><span class="term"><span><strong class="command">check-sibling</strong></span></span></dt>
3152 When performing integrity checks, also check that
3153 sibling glue exists. The default is <span><strong class="command">yes</strong></span>.
3155 <dt><span class="term"><span><strong class="command">zero-no-soa-ttl</strong></span></span></dt>
3157 When returning authoritative negative responses to
3158 SOA queries set the TTL of the SOA record returned in
3159 the authority section to zero.
3160 The default is <span><strong class="command">yes</strong></span>.
3162 <dt><span class="term"><span><strong class="command">zero-no-soa-ttl-cache</strong></span></span></dt>
3164 When caching a negative response to a SOA query
3165 set the TTL to zero.
3166 The default is <span><strong class="command">no</strong></span>.
3168 <dt><span class="term"><span><strong class="command">update-check-ksk</strong></span></span></dt>
3170 When regenerating the RRSIGs following a UPDATE
3171 request to a secure zone, check the KSK flag on
3172 the DNSKEY RR to determine if this key should be
3173 used to generate the RRSIG. This flag is ignored
3174 if there are not DNSKEY RRs both with and without
3176 The default is <span><strong class="command">yes</strong></span>.
3178 <dt><span class="term"><span><strong class="command">try-tcp-refresh</strong></span></span></dt>
3180 Try to refresh the zone using TCP if UDP queries fail.
3181 For BIND 8 compatibility, the default is
3182 <span><strong class="command">yes</strong></span>.
3186 <div class="sect3" lang="en">
3187 <div class="titlepage"><div><div><h4 class="title">
3188 <a name="id2581856"></a>Forwarding</h4></div></div></div>
3190 The forwarding facility can be used to create a large site-wide
3191 cache on a few servers, reducing traffic over links to external
3192 name servers. It can also be used to allow queries by servers that
3193 do not have direct access to the Internet, but wish to look up
3195 names anyway. Forwarding occurs only on those queries for which
3196 the server is not authoritative and does not have the answer in
3199 <div class="variablelist"><dl>
3200 <dt><span class="term"><span><strong class="command">forward</strong></span></span></dt>
3202 This option is only meaningful if the
3203 forwarders list is not empty. A value of <code class="varname">first</code>,
3204 the default, causes the server to query the forwarders
3206 if that doesn't answer the question, the server will then
3208 the answer itself. If <code class="varname">only</code> is
3210 server will only query the forwarders.
3212 <dt><span class="term"><span><strong class="command">forwarders</strong></span></span></dt>
3214 Specifies the IP addresses to be used
3215 for forwarding. The default is the empty list (no
3220 Forwarding can also be configured on a per-domain basis, allowing
3221 for the global forwarding options to be overridden in a variety
3222 of ways. You can set particular domains to use different
3224 or have a different <span><strong class="command">forward only/first</strong></span> behavior,
3225 or not forward at all, see <a href="Bv9ARM.ch06.html#zone_statement_grammar" title="zone
3226 Statement Grammar">the section called “<span><strong class="command">zone</strong></span>
3227 Statement Grammar”</a>.
3230 <div class="sect3" lang="en">
3231 <div class="titlepage"><div><div><h4 class="title">
3232 <a name="id2581914"></a>Dual-stack Servers</h4></div></div></div>
3234 Dual-stack servers are used as servers of last resort to work
3236 problems in reachability due the lack of support for either IPv4
3238 on the host machine.
3240 <div class="variablelist"><dl>
3241 <dt><span class="term"><span><strong class="command">dual-stack-servers</strong></span></span></dt>
3243 Specifies host names or addresses of machines with access to
3244 both IPv4 and IPv6 transports. If a hostname is used, the
3246 to resolve the name using only the transport it has. If the
3248 stacked, then the <span><strong class="command">dual-stack-servers</strong></span> have no effect unless
3249 access to a transport has been disabled on the command line
3250 (e.g. <span><strong class="command">named -4</strong></span>).
3254 <div class="sect3" lang="en">
3255 <div class="titlepage"><div><div><h4 class="title">
3256 <a name="access_control"></a>Access Control</h4></div></div></div>
3258 Access to the server can be restricted based on the IP address
3259 of the requesting system. See <a href="Bv9ARM.ch06.html#address_match_lists" title="Address Match Lists">the section called “Address Match Lists”</a> for
3260 details on how to specify IP address lists.
3262 <div class="variablelist"><dl>
3263 <dt><span class="term"><span><strong class="command">allow-notify</strong></span></span></dt>
3265 Specifies which hosts are allowed to
3266 notify this server, a slave, of zone changes in addition
3267 to the zone masters.
3268 <span><strong class="command">allow-notify</strong></span> may also be
3270 <span><strong class="command">zone</strong></span> statement, in which case
3272 <span><strong class="command">options allow-notify</strong></span>
3273 statement. It is only meaningful
3274 for a slave zone. If not specified, the default is to
3275 process notify messages
3276 only from a zone's master.
3278 <dt><span class="term"><span><strong class="command">allow-query</strong></span></span></dt>
3281 Specifies which hosts are allowed to ask ordinary
3282 DNS questions. <span><strong class="command">allow-query</strong></span> may
3283 also be specified in the <span><strong class="command">zone</strong></span>
3284 statement, in which case it overrides the
3285 <span><strong class="command">options allow-query</strong></span> statement.
3286 If not specified, the default is to allow queries
3289 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
3290 <h3 class="title">Note</h3>
3292 <span><strong class="command">allow-query-cache</strong></span> is now
3293 used to specify access to the cache.
3297 <dt><span class="term"><span><strong class="command">allow-query-on</strong></span></span></dt>
3300 Specifies which local addresses can accept ordinary
3301 DNS questions. This makes it possible, for instance,
3302 to allow queries on internal-facing interfaces but
3303 disallow them on external-facing ones, without
3304 necessarily knowing the internal network's addresses.
3307 <span><strong class="command">allow-query-on</strong></span> may
3308 also be specified in the <span><strong class="command">zone</strong></span>
3309 statement, in which case it overrides the
3310 <span><strong class="command">options allow-query-on</strong></span> statement.
3313 If not specified, the default is to allow queries
3316 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
3317 <h3 class="title">Note</h3>
3319 <span><strong class="command">allow-query-cache</strong></span> is
3320 used to specify access to the cache.
3324 <dt><span class="term"><span><strong class="command">allow-query-cache</strong></span></span></dt>
3326 Specifies which hosts are allowed to get answers
3327 from the cache. If <span><strong class="command">allow-query-cache</strong></span>
3328 is not set then <span><strong class="command">allow-recursion</strong></span>
3329 is used if set, otherwise <span><strong class="command">allow-query</strong></span>
3330 is used if set unless <span><strong class="command">recursion no;</strong></span> is
3331 set in which case <span><strong class="command">none;</strong></span> is used,
3332 otherwise the default (<span><strong class="command">localnets;</strong></span>
3333 <span><strong class="command">localhost;</strong></span>) is used.
3335 <dt><span class="term"><span><strong class="command">allow-query-cache-on</strong></span></span></dt>
3337 Specifies which local addresses can give answers
3338 from the cache. If not specified, the default is
3339 to allow cache queries on any address,
3340 <span><strong class="command">localnets</strong></span> and
3341 <span><strong class="command">localhost</strong></span>.
3343 <dt><span class="term"><span><strong class="command">allow-recursion</strong></span></span></dt>
3345 Specifies which hosts are allowed to make recursive
3346 queries through this server. If
3347 <span><strong class="command">allow-recursion</strong></span> is not set
3348 then <span><strong class="command">allow-query-cache</strong></span> is
3349 used if set, otherwise <span><strong class="command">allow-query</strong></span>
3350 is used if set, otherwise the default
3351 (<span><strong class="command">localnets;</strong></span>
3352 <span><strong class="command">localhost;</strong></span>) is used.
3354 <dt><span class="term"><span><strong class="command">allow-recursion-on</strong></span></span></dt>
3356 Specifies which local addresses can accept recursive
3357 queries. If not specified, the default is to allow
3358 recursive queries on all addresses.
3360 <dt><span class="term"><span><strong class="command">allow-update</strong></span></span></dt>
3362 Specifies which hosts are allowed to
3363 submit Dynamic DNS updates for master zones. The default is
3365 updates from all hosts. Note that allowing updates based
3366 on the requestor's IP address is insecure; see
3367 <a href="Bv9ARM.ch07.html#dynamic_update_security" title="Dynamic Update Security">the section called “Dynamic Update Security”</a> for details.
3369 <dt><span class="term"><span><strong class="command">allow-update-forwarding</strong></span></span></dt>
3372 Specifies which hosts are allowed to
3373 submit Dynamic DNS updates to slave zones to be forwarded to
3375 master. The default is <strong class="userinput"><code>{ none; }</code></strong>,
3377 means that no update forwarding will be performed. To
3379 update forwarding, specify
3380 <strong class="userinput"><code>allow-update-forwarding { any; };</code></strong>.
3381 Specifying values other than <strong class="userinput"><code>{ none; }</code></strong> or
3382 <strong class="userinput"><code>{ any; }</code></strong> is usually
3383 counterproductive, since
3384 the responsibility for update access control should rest
3386 master server, not the slaves.
3389 Note that enabling the update forwarding feature on a slave
3391 may expose master servers relying on insecure IP address
3393 access control to attacks; see <a href="Bv9ARM.ch07.html#dynamic_update_security" title="Dynamic Update Security">the section called “Dynamic Update Security”</a>
3397 <dt><span class="term"><span><strong class="command">allow-v6-synthesis</strong></span></span></dt>
3399 This option was introduced for the smooth transition from
3401 to A6 and from "nibble labels" to binary labels.
3402 However, since both A6 and binary labels were then
3404 this option was also deprecated.
3405 It is now ignored with some warning messages.
3407 <dt><span class="term"><span><strong class="command">allow-transfer</strong></span></span></dt>
3409 Specifies which hosts are allowed to
3410 receive zone transfers from the server. <span><strong class="command">allow-transfer</strong></span> may
3411 also be specified in the <span><strong class="command">zone</strong></span>
3413 case it overrides the <span><strong class="command">options allow-transfer</strong></span> statement.
3414 If not specified, the default is to allow transfers to all
3417 <dt><span class="term"><span><strong class="command">blackhole</strong></span></span></dt>
3419 Specifies a list of addresses that the
3420 server will not accept queries from or use to resolve a
3422 from these addresses will not be responded to. The default
3423 is <strong class="userinput"><code>none</code></strong>.
3427 <div class="sect3" lang="en">
3428 <div class="titlepage"><div><div><h4 class="title">
3429 <a name="id2582420"></a>Interfaces</h4></div></div></div>
3431 The interfaces and ports that the server will answer queries
3432 from may be specified using the <span><strong class="command">listen-on</strong></span> option. <span><strong class="command">listen-on</strong></span> takes
3433 an optional port and an <code class="varname">address_match_list</code>.
3434 The server will listen on all interfaces allowed by the address
3435 match list. If a port is not specified, port 53 will be used.
3438 Multiple <span><strong class="command">listen-on</strong></span> statements are
3442 <pre class="programlisting">listen-on { 5.6.7.8; };
3443 listen-on port 1234 { !1.2.3.4; 1.2/16; };
3446 will enable the name server on port 53 for the IP address
3447 5.6.7.8, and on port 1234 of an address on the machine in net
3448 1.2 that is not 1.2.3.4.
3451 If no <span><strong class="command">listen-on</strong></span> is specified, the
3452 server will listen on port 53 on all IPv4 interfaces.
3455 The <span><strong class="command">listen-on-v6</strong></span> option is used to
3456 specify the interfaces and the ports on which the server will
3458 for incoming queries sent using IPv6.
3462 <pre class="programlisting">{ any; }</pre>
3465 as the <code class="varname">address_match_list</code> for the
3466 <span><strong class="command">listen-on-v6</strong></span> option,
3467 the server does not bind a separate socket to each IPv6 interface
3468 address as it does for IPv4 if the operating system has enough API
3469 support for IPv6 (specifically if it conforms to RFC 3493 and RFC
3471 Instead, it listens on the IPv6 wildcard address.
3472 If the system only has incomplete API support for IPv6, however,
3473 the behavior is the same as that for IPv4.
3476 A list of particular IPv6 addresses can also be specified, in
3478 the server listens on a separate socket for each specified
3480 regardless of whether the desired API is supported by the system.
3483 Multiple <span><strong class="command">listen-on-v6</strong></span> options can
3487 <pre class="programlisting">listen-on-v6 { any; };
3488 listen-on-v6 port 1234 { !2001:db8::/32; any; };
3491 will enable the name server on port 53 for any IPv6 addresses
3492 (with a single wildcard socket),
3493 and on port 1234 of IPv6 addresses that is not in the prefix
3494 2001:db8::/32 (with separate sockets for each matched address.)
3497 To make the server not listen on any IPv6 address, use
3499 <pre class="programlisting">listen-on-v6 { none; };
3502 If no <span><strong class="command">listen-on-v6</strong></span> option is
3503 specified, the server will not listen on any IPv6 address
3504 unless <span><strong class="command">-6</strong></span> is specified when <span><strong class="command">named</strong></span> is
3505 invoked. If <span><strong class="command">-6</strong></span> is specified then
3506 <span><strong class="command">named</strong></span> will listen on port 53 on all IPv6 interfaces by default.
3509 <div class="sect3" lang="en">
3510 <div class="titlepage"><div><div><h4 class="title">
3511 <a name="query_address"></a>Query Address</h4></div></div></div>
3513 If the server doesn't know the answer to a question, it will
3514 query other name servers. <span><strong class="command">query-source</strong></span> specifies
3515 the address and port used for such queries. For queries sent over
3516 IPv6, there is a separate <span><strong class="command">query-source-v6</strong></span> option.
3517 If <span><strong class="command">address</strong></span> is <span><strong class="command">*</strong></span> (asterisk) or is omitted,
3518 a wildcard IP address (<span><strong class="command">INADDR_ANY</strong></span>)
3522 If <span><strong class="command">port</strong></span> is <span><strong class="command">*</strong></span> or is omitted,
3523 a random port number from a pre-configured
3524 range is picked up and will be used for each query.
3525 The port range(s) is that specified in
3526 the <span><strong class="command">use-v4-udp-ports</strong></span> (for IPv4)
3527 and <span><strong class="command">use-v6-udp-ports</strong></span> (for IPv6)
3528 options, excluding the ranges specified in
3529 the <span><strong class="command">avoid-v4-udp-ports</strong></span>
3530 and <span><strong class="command">avoid-v6-udp-ports</strong></span> options, respectively.
3533 The defaults of the <span><strong class="command">query-source</strong></span> and
3534 <span><strong class="command">query-source-v6</strong></span> options
3537 <pre class="programlisting">query-source address * port *;
3538 query-source-v6 address * port *;
3541 If <span><strong class="command">use-v4-udp-ports</strong></span> or
3542 <span><strong class="command">use-v6-udp-ports</strong></span> is unspecified,
3543 <span><strong class="command">named</strong></span> will check if the operating
3544 system provides a programming interface to retrieve the
3545 system's default range for ephemeral ports.
3546 If such an interface is available,
3547 <span><strong class="command">named</strong></span> will use the corresponding system
3548 default range; otherwise, it will use its own defaults:
3550 <pre class="programlisting">use-v4-udp-ports { range 1024 65535; };
3551 use-v6-udp-ports { range 1024 65535; };
3554 Note: make sure the ranges be sufficiently large for
3555 security. A desirable size depends on various parameters,
3556 but we generally recommend it contain at least 16384 ports
3557 (14 bits of entropy).
3558 Note also that the system's default range when used may be
3559 too small for this purpose, and that the range may even be
3560 changed while <span><strong class="command">named</strong></span> is running; the new
3561 range will automatically be applied when <span><strong class="command">named</strong></span>
3564 configure <span><strong class="command">use-v4-udp-ports</strong></span> and
3565 <span><strong class="command">use-v6-udp-ports</strong></span> explicitly so that the
3566 ranges are sufficiently large and are reasonably
3567 independent from the ranges used by other applications.
3570 Note: the operational configuration
3571 where <span><strong class="command">named</strong></span> runs may prohibit the use
3572 of some ports. For example, UNIX systems will not allow
3573 <span><strong class="command">named</strong></span> running without a root privilege
3574 to use ports less than 1024.
3575 If such ports are included in the specified (or detected)
3576 set of query ports, the corresponding query attempts will
3577 fail, resulting in resolution failures or delay.
3578 It is therefore important to configure the set of ports
3579 that can be safely used in the expected operational environment.
3582 The defaults of the <span><strong class="command">avoid-v4-udp-ports</strong></span> and
3583 <span><strong class="command">avoid-v6-udp-ports</strong></span> options
3586 <pre class="programlisting">avoid-v4-udp-ports {};
3587 avoid-v6-udp-ports {};
3590 Note: BIND 9.5.0 introduced
3591 the <span><strong class="command">use-queryport-pool</strong></span>
3592 option to support a pool of such random ports, but this
3593 option is now obsolete because reusing the same ports in
3594 the pool may not be sufficiently secure.
3595 For the same reason, it is generally strongly discouraged to
3596 specify a particular port for the
3597 <span><strong class="command">query-source</strong></span> or
3598 <span><strong class="command">query-source-v6</strong></span> options;
3599 it implicitly disables the use of randomized port numbers.
3601 <div class="variablelist"><dl>
3602 <dt><span class="term"><span><strong class="command">use-queryport-pool</strong></span></span></dt>
3604 This option is obsolete.
3606 <dt><span class="term"><span><strong class="command">queryport-pool-ports</strong></span></span></dt>
3608 This option is obsolete.
3610 <dt><span class="term"><span><strong class="command">queryport-pool-updateinterval</strong></span></span></dt>
3612 This option is obsolete.
3615 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
3616 <h3 class="title">Note</h3>
3618 The address specified in the <span><strong class="command">query-source</strong></span> option
3619 is used for both UDP and TCP queries, but the port applies only
3620 to UDP queries. TCP queries always use a random
3624 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
3625 <h3 class="title">Note</h3>
3627 Solaris 2.5.1 and earlier does not support setting the source
3628 address for TCP sockets.
3631 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
3632 <h3 class="title">Note</h3>
3634 See also <span><strong class="command">transfer-source</strong></span> and
3635 <span><strong class="command">notify-source</strong></span>.
3639 <div class="sect3" lang="en">
3640 <div class="titlepage"><div><div><h4 class="title">
3641 <a name="zone_transfers"></a>Zone Transfers</h4></div></div></div>
3643 <acronym class="acronym">BIND</acronym> has mechanisms in place to
3644 facilitate zone transfers
3645 and set limits on the amount of load that transfers place on the
3646 system. The following options apply to zone transfers.
3648 <div class="variablelist"><dl>
3649 <dt><span class="term"><span><strong class="command">also-notify</strong></span></span></dt>
3651 Defines a global list of IP addresses of name servers
3652 that are also sent NOTIFY messages whenever a fresh copy of
3654 zone is loaded, in addition to the servers listed in the
3656 This helps to ensure that copies of the zones will
3657 quickly converge on stealth servers.
3658 Optionally, a port may be specified with each
3659 <span><strong class="command">also-notify</strong></span> address to send
3660 the notify messages to a port other than the
3662 If an <span><strong class="command">also-notify</strong></span> list
3663 is given in a <span><strong class="command">zone</strong></span> statement,
3665 the <span><strong class="command">options also-notify</strong></span>
3666 statement. When a <span><strong class="command">zone notify</strong></span>
3668 is set to <span><strong class="command">no</strong></span>, the IP
3669 addresses in the global <span><strong class="command">also-notify</strong></span> list will
3670 not be sent NOTIFY messages for that zone. The default is
3672 list (no global notification list).
3674 <dt><span class="term"><span><strong class="command">max-transfer-time-in</strong></span></span></dt>
3676 Inbound zone transfers running longer than
3677 this many minutes will be terminated. The default is 120
3679 (2 hours). The maximum value is 28 days (40320 minutes).
3681 <dt><span class="term"><span><strong class="command">max-transfer-idle-in</strong></span></span></dt>
3683 Inbound zone transfers making no progress
3684 in this many minutes will be terminated. The default is 60
3686 (1 hour). The maximum value is 28 days (40320 minutes).
3688 <dt><span class="term"><span><strong class="command">max-transfer-time-out</strong></span></span></dt>
3690 Outbound zone transfers running longer than
3691 this many minutes will be terminated. The default is 120
3693 (2 hours). The maximum value is 28 days (40320 minutes).
3695 <dt><span class="term"><span><strong class="command">max-transfer-idle-out</strong></span></span></dt>
3697 Outbound zone transfers making no progress
3698 in this many minutes will be terminated. The default is 60
3700 hour). The maximum value is 28 days (40320 minutes).
3702 <dt><span class="term"><span><strong class="command">serial-query-rate</strong></span></span></dt>
3704 Slave servers will periodically query master servers
3705 to find out if zone serial numbers have changed. Each such
3707 a minute amount of the slave server's network bandwidth. To
3709 amount of bandwidth used, BIND 9 limits the rate at which
3711 sent. The value of the <span><strong class="command">serial-query-rate</strong></span> option,
3712 an integer, is the maximum number of queries sent per
3716 <dt><span class="term"><span><strong class="command">serial-queries</strong></span></span></dt>
3718 In BIND 8, the <span><strong class="command">serial-queries</strong></span>
3720 set the maximum number of concurrent serial number queries
3721 allowed to be outstanding at any given time.
3722 BIND 9 does not limit the number of outstanding
3723 serial queries and ignores the <span><strong class="command">serial-queries</strong></span> option.
3724 Instead, it limits the rate at which the queries are sent
3725 as defined using the <span><strong class="command">serial-query-rate</strong></span> option.
3727 <dt><span class="term"><span><strong class="command">transfer-format</strong></span></span></dt>
3729 Zone transfers can be sent using two different formats,
3730 <span><strong class="command">one-answer</strong></span> and
3731 <span><strong class="command">many-answers</strong></span>.
3732 The <span><strong class="command">transfer-format</strong></span> option is used
3733 on the master server to determine which format it sends.
3734 <span><strong class="command">one-answer</strong></span> uses one DNS message per
3735 resource record transferred.
3736 <span><strong class="command">many-answers</strong></span> packs as many resource
3737 records as possible into a message.
3738 <span><strong class="command">many-answers</strong></span> is more efficient, but is
3739 only supported by relatively new slave servers,
3740 such as <acronym class="acronym">BIND</acronym> 9, <acronym class="acronym">BIND</acronym>
3741 8.x and <acronym class="acronym">BIND</acronym> 4.9.5 onwards.
3742 The <span><strong class="command">many-answers</strong></span> format is also supported by
3743 recent Microsoft Windows nameservers.
3744 The default is <span><strong class="command">many-answers</strong></span>.
3745 <span><strong class="command">transfer-format</strong></span> may be overridden on a
3746 per-server basis by using the <span><strong class="command">server</strong></span>
3749 <dt><span class="term"><span><strong class="command">transfers-in</strong></span></span></dt>
3751 The maximum number of inbound zone transfers
3752 that can be running concurrently. The default value is <code class="literal">10</code>.
3753 Increasing <span><strong class="command">transfers-in</strong></span> may
3754 speed up the convergence
3755 of slave zones, but it also may increase the load on the
3758 <dt><span class="term"><span><strong class="command">transfers-out</strong></span></span></dt>
3760 The maximum number of outbound zone transfers
3761 that can be running concurrently. Zone transfer requests in
3763 of the limit will be refused. The default value is <code class="literal">10</code>.
3765 <dt><span class="term"><span><strong class="command">transfers-per-ns</strong></span></span></dt>
3767 The maximum number of inbound zone transfers
3768 that can be concurrently transferring from a given remote
3770 The default value is <code class="literal">2</code>.
3771 Increasing <span><strong class="command">transfers-per-ns</strong></span>
3773 speed up the convergence of slave zones, but it also may
3775 the load on the remote name server. <span><strong class="command">transfers-per-ns</strong></span> may
3776 be overridden on a per-server basis by using the <span><strong class="command">transfers</strong></span> phrase
3777 of the <span><strong class="command">server</strong></span> statement.
3779 <dt><span class="term"><span><strong class="command">transfer-source</strong></span></span></dt>
3781 <p><span><strong class="command">transfer-source</strong></span>
3782 determines which local address will be bound to IPv4
3783 TCP connections used to fetch zones transferred
3784 inbound by the server. It also determines the
3785 source IPv4 address, and optionally the UDP port,
3786 used for the refresh queries and forwarded dynamic
3787 updates. If not set, it defaults to a system
3788 controlled value which will usually be the address
3789 of the interface "closest to" the remote end. This
3790 address must appear in the remote end's
3791 <span><strong class="command">allow-transfer</strong></span> option for the
3792 zone being transferred, if one is specified. This
3794 <span><strong class="command">transfer-source</strong></span> for all zones,
3795 but can be overridden on a per-view or per-zone
3796 basis by including a
3797 <span><strong class="command">transfer-source</strong></span> statement within
3798 the <span><strong class="command">view</strong></span> or
3799 <span><strong class="command">zone</strong></span> block in the configuration
3802 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
3803 <h3 class="title">Note</h3>
3805 Solaris 2.5.1 and earlier does not support setting the
3806 source address for TCP sockets.
3810 <dt><span class="term"><span><strong class="command">transfer-source-v6</strong></span></span></dt>
3812 The same as <span><strong class="command">transfer-source</strong></span>,
3813 except zone transfers are performed using IPv6.
3815 <dt><span class="term"><span><strong class="command">alt-transfer-source</strong></span></span></dt>
3818 An alternate transfer source if the one listed in
3819 <span><strong class="command">transfer-source</strong></span> fails and
3820 <span><strong class="command">use-alt-transfer-source</strong></span> is
3823 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
3824 <h3 class="title">Note</h3>
3825 If you do not wish the alternate transfer source
3826 to be used, you should set
3827 <span><strong class="command">use-alt-transfer-source</strong></span>
3828 appropriately and you should not depend upon
3829 getting an answer back to the first refresh
3833 <dt><span class="term"><span><strong class="command">alt-transfer-source-v6</strong></span></span></dt>
3835 An alternate transfer source if the one listed in
3836 <span><strong class="command">transfer-source-v6</strong></span> fails and
3837 <span><strong class="command">use-alt-transfer-source</strong></span> is
3840 <dt><span class="term"><span><strong class="command">use-alt-transfer-source</strong></span></span></dt>
3842 Use the alternate transfer sources or not. If views are
3843 specified this defaults to <span><strong class="command">no</strong></span>
3844 otherwise it defaults to
3845 <span><strong class="command">yes</strong></span> (for BIND 8
3848 <dt><span class="term"><span><strong class="command">notify-source</strong></span></span></dt>
3850 <p><span><strong class="command">notify-source</strong></span>
3851 determines which local source address, and
3852 optionally UDP port, will be used to send NOTIFY
3853 messages. This address must appear in the slave
3854 server's <span><strong class="command">masters</strong></span> zone clause or
3855 in an <span><strong class="command">allow-notify</strong></span> clause. This
3856 statement sets the <span><strong class="command">notify-source</strong></span>
3857 for all zones, but can be overridden on a per-zone or
3858 per-view basis by including a
3859 <span><strong class="command">notify-source</strong></span> statement within
3860 the <span><strong class="command">zone</strong></span> or
3861 <span><strong class="command">view</strong></span> block in the configuration
3864 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
3865 <h3 class="title">Note</h3>
3867 Solaris 2.5.1 and earlier does not support setting the
3868 source address for TCP sockets.
3872 <dt><span class="term"><span><strong class="command">notify-source-v6</strong></span></span></dt>
3874 Like <span><strong class="command">notify-source</strong></span>,
3875 but applies to notify messages sent to IPv6 addresses.
3879 <div class="sect3" lang="en">
3880 <div class="titlepage"><div><div><h4 class="title">
3881 <a name="id2583691"></a>UDP Port Lists</h4></div></div></div>
3883 <span><strong class="command">use-v4-udp-ports</strong></span>,
3884 <span><strong class="command">avoid-v4-udp-ports</strong></span>,
3885 <span><strong class="command">use-v6-udp-ports</strong></span>, and
3886 <span><strong class="command">avoid-v6-udp-ports</strong></span>
3887 specify a list of IPv4 and IPv6 UDP ports that will be
3888 used or not used as source ports for UDP messages.
3889 See <a href="Bv9ARM.ch06.html#query_address" title="Query Address">the section called “Query Address”</a> about how the
3890 available ports are determined.
3891 For example, with the following configuration
3893 <pre class="programlisting">
3894 use-v6-udp-ports { range 32768 65535; };
3895 avoid-v6-udp-ports { 40000; range 50000 60000; };
3898 UDP ports of IPv6 messages sent
3899 from <span><strong class="command">named</strong></span> will be in one
3900 of the following ranges: 32768 to 39999, 40001 to 49999,
3904 <span><strong class="command">avoid-v4-udp-ports</strong></span> and
3905 <span><strong class="command">avoid-v6-udp-ports</strong></span> can be used
3906 to prevent <span><strong class="command">named</strong></span> from choosing as its random source port a
3907 port that is blocked by your firewall or a port that is
3908 used by other applications;
3909 if a query went out with a source port blocked by a
3911 answer would not get by the firewall and the name server would
3912 have to query again.
3913 Note: the desired range can also be represented only with
3914 <span><strong class="command">use-v4-udp-ports</strong></span> and
3915 <span><strong class="command">use-v6-udp-ports</strong></span>, and the
3916 <span><strong class="command">avoid-</strong></span> options are redundant in that
3917 sense; they are provided for backward compatibility and
3918 to possibly simplify the port specification.
3921 <div class="sect3" lang="en">
3922 <div class="titlepage"><div><div><h4 class="title">
3923 <a name="id2583751"></a>Operating System Resource Limits</h4></div></div></div>
3925 The server's usage of many system resources can be limited.
3926 Scaled values are allowed when specifying resource limits. For
3927 example, <span><strong class="command">1G</strong></span> can be used instead of
3928 <span><strong class="command">1073741824</strong></span> to specify a limit of
3930 gigabyte. <span><strong class="command">unlimited</strong></span> requests
3931 unlimited use, or the
3932 maximum available amount. <span><strong class="command">default</strong></span>
3934 that was in force when the server was started. See the description
3935 of <span><strong class="command">size_spec</strong></span> in <a href="Bv9ARM.ch06.html#configuration_file_elements" title="Configuration File Elements">the section called “Configuration File Elements”</a>.
3938 The following options set operating system resource limits for
3939 the name server process. Some operating systems don't support
3941 any of the limits. On such systems, a warning will be issued if
3943 unsupported limit is used.
3945 <div class="variablelist"><dl>
3946 <dt><span class="term"><span><strong class="command">coresize</strong></span></span></dt>
3948 The maximum size of a core dump. The default
3949 is <code class="literal">default</code>.
3951 <dt><span class="term"><span><strong class="command">datasize</strong></span></span></dt>
3953 The maximum amount of data memory the server
3954 may use. The default is <code class="literal">default</code>.
3955 This is a hard limit on server memory usage.
3956 If the server attempts to allocate memory in excess of this
3957 limit, the allocation will fail, which may in turn leave
3958 the server unable to perform DNS service. Therefore,
3959 this option is rarely useful as a way of limiting the
3960 amount of memory used by the server, but it can be used
3961 to raise an operating system data size limit that is
3962 too small by default. If you wish to limit the amount
3963 of memory used by the server, use the
3964 <span><strong class="command">max-cache-size</strong></span> and
3965 <span><strong class="command">recursive-clients</strong></span>
3968 <dt><span class="term"><span><strong class="command">files</strong></span></span></dt>
3970 The maximum number of files the server
3971 may have open concurrently. The default is <code class="literal">unlimited</code>.
3973 <dt><span class="term"><span><strong class="command">stacksize</strong></span></span></dt>
3975 The maximum amount of stack memory the server
3976 may use. The default is <code class="literal">default</code>.
3980 <div class="sect3" lang="en">
3981 <div class="titlepage"><div><div><h4 class="title">
3982 <a name="server_resource_limits"></a>Server Resource Limits</h4></div></div></div>
3984 The following options set limits on the server's
3985 resource consumption that are enforced internally by the
3986 server rather than the operating system.
3988 <div class="variablelist"><dl>
3989 <dt><span class="term"><span><strong class="command">max-ixfr-log-size</strong></span></span></dt>
3991 This option is obsolete; it is accepted
3992 and ignored for BIND 8 compatibility. The option
3993 <span><strong class="command">max-journal-size</strong></span> performs a
3994 similar function in BIND 9.
3996 <dt><span class="term"><span><strong class="command">max-journal-size</strong></span></span></dt>
3998 Sets a maximum size for each journal file
3999 (see <a href="Bv9ARM.ch04.html#journal" title="The journal file">the section called “The journal file”</a>). When the journal file
4001 the specified size, some of the oldest transactions in the
4003 will be automatically removed. The default is
4004 <code class="literal">unlimited</code>.
4005 This may also be set on a per-zone basis.
4007 <dt><span class="term"><span><strong class="command">host-statistics-max</strong></span></span></dt>
4009 In BIND 8, specifies the maximum number of host statistics
4011 Not implemented in BIND 9.
4013 <dt><span class="term"><span><strong class="command">recursive-clients</strong></span></span></dt>
4015 The maximum number of simultaneous recursive lookups
4016 the server will perform on behalf of clients. The default
4018 <code class="literal">1000</code>. Because each recursing
4020 bit of memory, on the order of 20 kilobytes, the value of
4022 <span><strong class="command">recursive-clients</strong></span> option may
4023 have to be decreased
4024 on hosts with limited memory.
4026 <dt><span class="term"><span><strong class="command">tcp-clients</strong></span></span></dt>
4028 The maximum number of simultaneous client TCP
4029 connections that the server will accept.
4030 The default is <code class="literal">100</code>.
4032 <dt><span class="term"><span><strong class="command">reserved-sockets</strong></span></span></dt>
4035 The number of file descriptors reserved for TCP, stdio,
4036 etc. This needs to be big enough to cover the number of
4037 interfaces <span><strong class="command">named</strong></span> listens on, <span><strong class="command">tcp-clients</strong></span> as well as
4038 to provide room for outgoing TCP queries and incoming zone
4039 transfers. The default is <code class="literal">512</code>.
4040 The minimum value is <code class="literal">128</code> and the
4041 maximum value is <code class="literal">128</code> less than
4042 maxsockets (-S). This option may be removed in the future.
4045 This option has little effect on Windows.
4048 <dt><span class="term"><span><strong class="command">max-cache-size</strong></span></span></dt>
4050 The maximum amount of memory to use for the
4051 server's cache, in bytes.
4052 When the amount of data in the cache
4053 reaches this limit, the server will cause records to expire
4054 prematurely based on an LRU based strategy so that
4055 the limit is not exceeded.
4056 A value of 0 is special, meaning that
4057 records are purged from the cache only when their
4059 Another special keyword <strong class="userinput"><code>unlimited</code></strong>
4060 means the maximum value of 32-bit unsigned integers
4061 (0xffffffff), which may not have the same effect as
4062 0 on machines that support more than 32 bits of
4064 Any positive values less than 2MB will be ignored reset
4066 In a server with multiple views, the limit applies
4067 separately to the cache of each view.
4070 <dt><span class="term"><span><strong class="command">tcp-listen-queue</strong></span></span></dt>
4072 The listen queue depth. The default and minimum is 3.
4073 If the kernel supports the accept filter "dataready" this
4075 many TCP connections that will be queued in kernel space
4077 some data before being passed to accept. Values less than 3
4083 <div class="sect3" lang="en">
4084 <div class="titlepage"><div><div><h4 class="title">
4085 <a name="id2584173"></a>Periodic Task Intervals</h4></div></div></div>
4086 <div class="variablelist"><dl>
4087 <dt><span class="term"><span><strong class="command">cleaning-interval</strong></span></span></dt>
4089 This interval is effectively obsolete. Previously,
4090 the server would remove expired resource records
4091 from the cache every <span><strong class="command">cleaning-interval</strong></span> minutes.
4092 <acronym class="acronym">BIND</acronym> 9 now manages cache
4093 memory in a more sophisticated manner and does not
4094 rely on the periodic cleaning any more.
4095 Specifying this option therefore has no effect on
4096 the server's behavior.
4098 <dt><span class="term"><span><strong class="command">heartbeat-interval</strong></span></span></dt>
4100 The server will perform zone maintenance tasks
4101 for all zones marked as <span><strong class="command">dialup</strong></span> whenever this
4102 interval expires. The default is 60 minutes. Reasonable
4104 to 1 day (1440 minutes). The maximum value is 28 days
4106 If set to 0, no zone maintenance for these zones will occur.
4108 <dt><span class="term"><span><strong class="command">interface-interval</strong></span></span></dt>
4110 The server will scan the network interface list
4111 every <span><strong class="command">interface-interval</strong></span>
4112 minutes. The default
4113 is 60 minutes. The maximum value is 28 days (40320 minutes).
4114 If set to 0, interface scanning will only occur when
4115 the configuration file is loaded. After the scan, the
4117 begin listening for queries on any newly discovered
4118 interfaces (provided they are allowed by the
4119 <span><strong class="command">listen-on</strong></span> configuration), and
4121 stop listening on interfaces that have gone away.
4123 <dt><span class="term"><span><strong class="command">statistics-interval</strong></span></span></dt>
4126 Name server statistics will be logged
4127 every <span><strong class="command">statistics-interval</strong></span>
4128 minutes. The default is
4129 60. The maximum value is 28 days (40320 minutes).
4130 If set to 0, no statistics will be logged.
4132 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
4133 <h3 class="title">Note</h3>
4135 Not yet implemented in
4136 <acronym class="acronym">BIND</acronym> 9.
4142 <div class="sect3" lang="en">
4143 <div class="titlepage"><div><div><h4 class="title">
4144 <a name="topology"></a>Topology</h4></div></div></div>
4146 All other things being equal, when the server chooses a name
4148 to query from a list of name servers, it prefers the one that is
4149 topologically closest to itself. The <span><strong class="command">topology</strong></span> statement
4150 takes an <span><strong class="command">address_match_list</strong></span> and
4152 in a special way. Each top-level list element is assigned a
4154 Non-negated elements get a distance based on their position in the
4155 list, where the closer the match is to the start of the list, the
4156 shorter the distance is between it and the server. A negated match
4157 will be assigned the maximum distance from the server. If there
4158 is no match, the address will get a distance which is further than
4159 any non-negated list element, and closer than any negated element.
4162 <pre class="programlisting">topology {
4168 will prefer servers on network 10 the most, followed by hosts
4169 on network 1.2.0.0 (netmask 255.255.0.0) and network 3, with the
4170 exception of hosts on network 1.2.3 (netmask 255.255.255.0), which
4171 is preferred least of all.
4174 The default topology is
4176 <pre class="programlisting"> topology { localhost; localnets; };
4178 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
4179 <h3 class="title">Note</h3>
4181 The <span><strong class="command">topology</strong></span> option
4182 is not implemented in <acronym class="acronym">BIND</acronym> 9.
4186 <div class="sect3" lang="en">
4187 <div class="titlepage"><div><div><h4 class="title">
4188 <a name="the_sortlist_statement"></a>The <span><strong class="command">sortlist</strong></span> Statement</h4></div></div></div>
4190 The response to a DNS query may consist of multiple resource
4191 records (RRs) forming a resource records set (RRset).
4192 The name server will normally return the
4193 RRs within the RRset in an indeterminate order
4194 (but see the <span><strong class="command">rrset-order</strong></span>
4195 statement in <a href="Bv9ARM.ch06.html#rrset_ordering" title="RRset Ordering">the section called “RRset Ordering”</a>).
4196 The client resolver code should rearrange the RRs as appropriate,
4197 that is, using any addresses on the local net in preference to
4199 However, not all resolvers can do this or are correctly
4201 When a client is using a local server, the sorting can be performed
4202 in the server, based on the client's address. This only requires
4203 configuring the name servers, not all the clients.
4206 The <span><strong class="command">sortlist</strong></span> statement (see below)
4208 an <span><strong class="command">address_match_list</strong></span> and
4210 more specifically than the <span><strong class="command">topology</strong></span>
4212 does (<a href="Bv9ARM.ch06.html#topology" title="Topology">the section called “Topology”</a>).
4213 Each top level statement in the <span><strong class="command">sortlist</strong></span> must
4214 itself be an explicit <span><strong class="command">address_match_list</strong></span> with
4215 one or two elements. The first element (which may be an IP
4217 an IP prefix, an ACL name or a nested <span><strong class="command">address_match_list</strong></span>)
4218 of each top level list is checked against the source address of
4219 the query until a match is found.
4222 Once the source address of the query has been matched, if
4223 the top level statement contains only one element, the actual
4225 element that matched the source address is used to select the
4227 in the response to move to the beginning of the response. If the
4228 statement is a list of two elements, then the second element is
4229 treated the same as the <span><strong class="command">address_match_list</strong></span> in
4230 a <span><strong class="command">topology</strong></span> statement. Each top
4232 is assigned a distance and the address in the response with the
4234 distance is moved to the beginning of the response.
4237 In the following example, any queries received from any of
4238 the addresses of the host itself will get responses preferring
4240 on any of the locally connected networks. Next most preferred are
4242 on the 192.168.1/24 network, and after that either the
4245 192.168.3/24 network with no preference shown between these two
4246 networks. Queries received from a host on the 192.168.1/24 network
4247 will prefer other addresses on that network to the 192.168.2/24
4249 192.168.3/24 networks. Queries received from a host on the
4251 or the 192.168.5/24 network will only prefer other addresses on
4252 their directly connected networks.
4254 <pre class="programlisting">sortlist {
4255 { localhost; // IF the local host
4256 { localnets; // THEN first fit on the
4257 192.168.1/24; // following nets
4258 { 192.168.2/24; 192.168.3/24; }; }; };
4259 { 192.168.1/24; // IF on class C 192.168.1
4260 { 192.168.1/24; // THEN use .1, or .2 or .3
4261 { 192.168.2/24; 192.168.3/24; }; }; };
4262 { 192.168.2/24; // IF on class C 192.168.2
4263 { 192.168.2/24; // THEN use .2, or .1 or .3
4264 { 192.168.1/24; 192.168.3/24; }; }; };
4265 { 192.168.3/24; // IF on class C 192.168.3
4266 { 192.168.3/24; // THEN use .3, or .1 or .2
4267 { 192.168.1/24; 192.168.2/24; }; }; };
4268 { { 192.168.4/24; 192.168.5/24; }; // if .4 or .5, prefer that net
4272 The following example will give reasonable behavior for the
4273 local host and hosts on directly connected networks. It is similar
4274 to the behavior of the address sort in <acronym class="acronym">BIND</acronym> 4.9.x. Responses sent
4275 to queries from the local host will favor any of the directly
4277 networks. Responses sent to queries from any other hosts on a
4279 connected network will prefer addresses on that same network.
4281 to other queries will not be sorted.
4283 <pre class="programlisting">sortlist {
4284 { localhost; localnets; };
4289 <div class="sect3" lang="en">
4290 <div class="titlepage"><div><div><h4 class="title">
4291 <a name="rrset_ordering"></a>RRset Ordering</h4></div></div></div>
4293 When multiple records are returned in an answer it may be
4294 useful to configure the order of the records placed into the
4296 The <span><strong class="command">rrset-order</strong></span> statement permits
4298 of the ordering of the records in a multiple record response.
4299 See also the <span><strong class="command">sortlist</strong></span> statement,
4300 <a href="Bv9ARM.ch06.html#the_sortlist_statement" title="The sortlist Statement">the section called “The <span><strong class="command">sortlist</strong></span> Statement”</a>.
4303 An <span><strong class="command">order_spec</strong></span> is defined as
4307 [<span class="optional">class <em class="replaceable"><code>class_name</code></em></span>]
4308 [<span class="optional">type <em class="replaceable"><code>type_name</code></em></span>]
4309 [<span class="optional">name <em class="replaceable"><code>"domain_name"</code></em></span>]
4310 order <em class="replaceable"><code>ordering</code></em>
4313 If no class is specified, the default is <span><strong class="command">ANY</strong></span>.
4314 If no type is specified, the default is <span><strong class="command">ANY</strong></span>.
4315 If no name is specified, the default is "<span><strong class="command">*</strong></span>" (asterisk).
4318 The legal values for <span><strong class="command">ordering</strong></span> are:
4320 <div class="informaltable"><table border="1">
4328 <p><span><strong class="command">fixed</strong></span></p>
4332 Records are returned in the order they
4333 are defined in the zone file.
4339 <p><span><strong class="command">random</strong></span></p>
4343 Records are returned in some random order.
4349 <p><span><strong class="command">cyclic</strong></span></p>
4353 Records are returned in a cyclic round-robin order.
4356 If <acronym class="acronym">BIND</acronym> is configured with the
4357 "--enable-fixed-rrset" option at compile time, then
4358 the initial ordering of the RRset will match the
4359 one specified in the zone file.
4368 <pre class="programlisting">rrset-order {
4369 class IN type A name "host.example.com" order random;
4374 will cause any responses for type A records in class IN that
4375 have "<code class="literal">host.example.com</code>" as a
4376 suffix, to always be returned
4377 in random order. All other records are returned in cyclic order.
4380 If multiple <span><strong class="command">rrset-order</strong></span> statements
4382 they are not combined — the last one applies.
4384 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
4385 <h3 class="title">Note</h3>
4387 In this release of <acronym class="acronym">BIND</acronym> 9, the
4388 <span><strong class="command">rrset-order</strong></span> statement does not support
4389 "fixed" ordering by default. Fixed ordering can be enabled
4390 at compile time by specifying "--enable-fixed-rrset" on
4391 the "configure" command line.
4395 <div class="sect3" lang="en">
4396 <div class="titlepage"><div><div><h4 class="title">
4397 <a name="tuning"></a>Tuning</h4></div></div></div>
4398 <div class="variablelist"><dl>
4399 <dt><span class="term"><span><strong class="command">lame-ttl</strong></span></span></dt>
4402 Sets the number of seconds to cache a
4403 lame server indication. 0 disables caching. (This is
4404 <span class="bold"><strong>NOT</strong></span> recommended.)
4405 The default is <code class="literal">600</code> (10 minutes) and the
4407 <code class="literal">1800</code> (30 minutes).
4410 Lame-ttl also controls the amount of time DNSSEC
4411 validation failures are cached. There is a minimum
4412 of 30 seconds applied to bad cache entries if the
4413 lame-ttl is set to less than 30 seconds.
4416 <dt><span class="term"><span><strong class="command">max-ncache-ttl</strong></span></span></dt>
4418 To reduce network traffic and increase performance,
4419 the server stores negative answers. <span><strong class="command">max-ncache-ttl</strong></span> is
4420 used to set a maximum retention time for these answers in
4422 in seconds. The default
4423 <span><strong class="command">max-ncache-ttl</strong></span> is <code class="literal">10800</code> seconds (3 hours).
4424 <span><strong class="command">max-ncache-ttl</strong></span> cannot exceed
4426 be silently truncated to 7 days if set to a greater value.
4428 <dt><span class="term"><span><strong class="command">max-cache-ttl</strong></span></span></dt>
4430 Sets the maximum time for which the server will
4431 cache ordinary (positive) answers. The default is
4433 A value of zero may cause all queries to return
4434 SERVFAIL, because of lost caches of intermediate
4435 RRsets (such as NS and glue AAAA/A records) in the
4438 <dt><span class="term"><span><strong class="command">min-roots</strong></span></span></dt>
4441 The minimum number of root servers that
4442 is required for a request for the root servers to be
4443 accepted. The default
4444 is <strong class="userinput"><code>2</code></strong>.
4446 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
4447 <h3 class="title">Note</h3>
4449 Not implemented in <acronym class="acronym">BIND</acronym> 9.
4453 <dt><span class="term"><span><strong class="command">sig-validity-interval</strong></span></span></dt>
4456 Specifies the number of days into the future when
4457 DNSSEC signatures automatically generated as a
4458 result of dynamic updates (<a href="Bv9ARM.ch04.html#dynamic_update" title="Dynamic Update">the section called “Dynamic Update”</a>) will expire. There
4459 is a optional second field which specifies how
4460 long before expiry that the signatures will be
4461 regenerated. If not specified, the signatures will
4462 be regenerated at 1/4 of base interval. The second
4463 field is specified in days if the base interval is
4464 greater than 7 days otherwise it is specified in hours.
4465 The default base interval is <code class="literal">30</code> days
4466 giving a re-signing interval of 7 1/2 days. The maximum
4467 values are 10 years (3660 days).
4470 The signature inception time is unconditionally
4471 set to one hour before the current time to allow
4472 for a limited amount of clock skew.
4475 The <span><strong class="command">sig-validity-interval</strong></span>
4476 should be, at least, several multiples of the SOA
4477 expire interval to allow for reasonable interaction
4478 between the various timer and expiry dates.
4481 <dt><span class="term"><span><strong class="command">sig-signing-nodes</strong></span></span></dt>
4483 Specify the maximum number of nodes to be
4484 examined in each quantum when signing a zone with
4485 a new DNSKEY. The default is
4486 <code class="literal">100</code>.
4488 <dt><span class="term"><span><strong class="command">sig-signing-signatures</strong></span></span></dt>
4490 Specify a threshold number of signatures that
4491 will terminate processing a quantum when signing
4492 a zone with a new DNSKEY. The default is
4493 <code class="literal">10</code>.
4495 <dt><span class="term"><span><strong class="command">sig-signing-type</strong></span></span></dt>
4498 Specify a private RDATA type to be used when generating
4499 key signing records. The default is
4500 <code class="literal">65535</code>.
4503 It is expected that this parameter may be removed
4504 in a future version once there is a standard type.
4508 <span class="term"><span><strong class="command">min-refresh-time</strong></span>, </span><span class="term"><span><strong class="command">max-refresh-time</strong></span>, </span><span class="term"><span><strong class="command">min-retry-time</strong></span>, </span><span class="term"><span><strong class="command">max-retry-time</strong></span></span>
4512 These options control the server's behavior on refreshing a
4514 (querying for SOA changes) or retrying failed transfers.
4515 Usually the SOA values for the zone are used, but these
4517 are set by the master, giving slave server administrators
4519 control over their contents.
4522 These options allow the administrator to set a minimum and
4524 refresh and retry time either per-zone, per-view, or
4526 These options are valid for slave and stub zones,
4527 and clamp the SOA refresh and retry times to the specified
4531 <dt><span class="term"><span><strong class="command">edns-udp-size</strong></span></span></dt>
4533 Sets the advertised EDNS UDP buffer size in bytes
4534 to control the size of packets received.
4535 Valid values are 512 to 4096 (values outside this range
4536 will be silently adjusted). The default value
4537 is 4096. The usual reason for setting
4538 <span><strong class="command">edns-udp-size</strong></span> to a non-default
4539 value is to get UDP answers to pass through broken
4540 firewalls that block fragmented packets and/or
4541 block UDP packets that are greater than 512 bytes.
4543 <dt><span class="term"><span><strong class="command">max-udp-size</strong></span></span></dt>
4545 Sets the maximum EDNS UDP message size <span><strong class="command">named</strong></span> will
4546 send in bytes. Valid values are 512 to 4096 (values outside
4547 this range will be silently adjusted). The default
4548 value is 4096. The usual reason for setting
4549 <span><strong class="command">max-udp-size</strong></span> to a non-default value is to get UDP
4550 answers to pass through broken firewalls that
4551 block fragmented packets and/or block UDP packets
4552 that are greater than 512 bytes.
4553 This is independent of the advertised receive
4554 buffer (<span><strong class="command">edns-udp-size</strong></span>).
4556 <dt><span class="term"><span><strong class="command">masterfile-format</strong></span></span></dt>
4558 the file format of zone files (see
4559 <a href="Bv9ARM.ch06.html#zonefile_format" title="Additional File Formats">the section called “Additional File Formats”</a>).
4560 The default value is <code class="constant">text</code>, which is the
4561 standard textual representation. Files in other formats
4562 than <code class="constant">text</code> are typically expected
4563 to be generated by the <span><strong class="command">named-compilezone</strong></span> tool.
4564 Note that when a zone file in a different format than
4565 <code class="constant">text</code> is loaded, <span><strong class="command">named</strong></span>
4566 may omit some of the checks which would be performed for a
4567 file in the <code class="constant">text</code> format. In particular,
4568 <span><strong class="command">check-names</strong></span> checks do not apply
4569 for the <code class="constant">raw</code> format. This means
4570 a zone file in the <code class="constant">raw</code> format
4571 must be generated with the same check level as that
4572 specified in the <span><strong class="command">named</strong></span> configuration
4573 file. This statement sets the
4574 <span><strong class="command">masterfile-format</strong></span> for all zones,
4575 but can be overridden on a per-zone or per-view basis
4576 by including a <span><strong class="command">masterfile-format</strong></span>
4577 statement within the <span><strong class="command">zone</strong></span> or
4578 <span><strong class="command">view</strong></span> block in the configuration
4582 <a name="clients-per-query"></a><span class="term"><span><strong class="command">clients-per-query</strong></span>, </span><span class="term"><span><strong class="command">max-clients-per-query</strong></span></span>
4586 initial value (minimum) and maximum number of recursive
4587 simultaneous clients for any given query
4588 (<qname,qtype,qclass>) that the server will accept
4589 before dropping additional clients. <span><strong class="command">named</strong></span> will attempt to
4590 self tune this value and changes will be logged. The
4591 default values are 10 and 100.
4594 This value should reflect how many queries come in for
4595 a given name in the time it takes to resolve that name.
4596 If the number of queries exceed this value, <span><strong class="command">named</strong></span> will
4597 assume that it is dealing with a non-responsive zone
4598 and will drop additional queries. If it gets a response
4599 after dropping queries, it will raise the estimate. The
4600 estimate will then be lowered in 20 minutes if it has
4604 If <span><strong class="command">clients-per-query</strong></span> is set to zero,
4605 then there is no limit on the number of clients per query
4606 and no queries will be dropped.
4609 If <span><strong class="command">max-clients-per-query</strong></span> is set to zero,
4610 then there is no upper bound other than imposed by
4611 <span><strong class="command">recursive-clients</strong></span>.
4614 <dt><span class="term"><span><strong class="command">notify-delay</strong></span></span></dt>
4616 The delay, in seconds, between sending sets of notify
4617 messages for a zone. The default is five (5) seconds.
4621 <div class="sect3" lang="en">
4622 <div class="titlepage"><div><div><h4 class="title">
4623 <a name="builtin"></a>Built-in server information zones</h4></div></div></div>
4625 The server provides some helpful diagnostic information
4626 through a number of built-in zones under the
4627 pseudo-top-level-domain <code class="literal">bind</code> in the
4628 <span><strong class="command">CHAOS</strong></span> class. These zones are part
4630 built-in view (see <a href="Bv9ARM.ch06.html#view_statement_grammar" title="view Statement Grammar">the section called “<span><strong class="command">view</strong></span> Statement Grammar”</a>) of
4632 <span><strong class="command">CHAOS</strong></span> which is separate from the
4634 class <span><strong class="command">IN</strong></span>; therefore, any global
4636 such as <span><strong class="command">allow-query</strong></span> do not apply
4638 If you feel the need to disable these zones, use the options
4639 below, or hide the built-in <span><strong class="command">CHAOS</strong></span>
4641 defining an explicit view of class <span><strong class="command">CHAOS</strong></span>
4642 that matches all clients.
4644 <div class="variablelist"><dl>
4645 <dt><span class="term"><span><strong class="command">version</strong></span></span></dt>
4647 The version the server should report
4648 via a query of the name <code class="literal">version.bind</code>
4649 with type <span><strong class="command">TXT</strong></span>, class <span><strong class="command">CHAOS</strong></span>.
4650 The default is the real version number of this server.
4651 Specifying <span><strong class="command">version none</strong></span>
4652 disables processing of the queries.
4654 <dt><span class="term"><span><strong class="command">hostname</strong></span></span></dt>
4656 The hostname the server should report via a query of
4657 the name <code class="filename">hostname.bind</code>
4658 with type <span><strong class="command">TXT</strong></span>, class <span><strong class="command">CHAOS</strong></span>.
4659 This defaults to the hostname of the machine hosting the
4661 found by the gethostname() function. The primary purpose of such queries
4663 identify which of a group of anycast servers is actually
4664 answering your queries. Specifying <span><strong class="command">hostname none;</strong></span>
4665 disables processing of the queries.
4667 <dt><span class="term"><span><strong class="command">server-id</strong></span></span></dt>
4669 The ID the server should report when receiving a Name
4670 Server Identifier (NSID) query, or a query of the name
4671 <code class="filename">ID.SERVER</code> with type
4672 <span><strong class="command">TXT</strong></span>, class <span><strong class="command">CHAOS</strong></span>.
4673 The primary purpose of such queries is to
4674 identify which of a group of anycast servers is actually
4675 answering your queries. Specifying <span><strong class="command">server-id none;</strong></span>
4676 disables processing of the queries.
4677 Specifying <span><strong class="command">server-id hostname;</strong></span> will cause <span><strong class="command">named</strong></span> to
4678 use the hostname as found by the gethostname() function.
4679 The default <span><strong class="command">server-id</strong></span> is <span><strong class="command">none</strong></span>.
4683 <div class="sect3" lang="en">
4684 <div class="titlepage"><div><div><h4 class="title">
4685 <a name="empty"></a>Built-in Empty Zones</h4></div></div></div>
4687 Named has some built-in empty zones (SOA and NS records only).
4688 These are for zones that should normally be answered locally
4689 and which queries should not be sent to the Internet's root
4690 servers. The official servers which cover these namespaces
4691 return NXDOMAIN responses to these queries. In particular,
4692 these cover the reverse namespace for addresses from RFC 1918 and
4693 RFC 3330. They also include the reverse namespace for IPv6 local
4694 address (locally assigned), IPv6 link local addresses, the IPv6
4695 loopback address and the IPv6 unknown address.
4698 Named will attempt to determine if a built-in zone already exists
4699 or is active (covered by a forward-only forwarding declaration)
4700 and will not create a empty zone in that case.
4703 The current list of empty zones is:
4705 <div class="itemizedlist"><ul type="disc">
4706 <li>0.IN-ADDR.ARPA</li>
4707 <li>127.IN-ADDR.ARPA</li>
4708 <li>254.169.IN-ADDR.ARPA</li>
4709 <li>2.0.192.IN-ADDR.ARPA</li>
4710 <li>255.255.255.255.IN-ADDR.ARPA</li>
4711 <li>0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.IP6.ARPA</li>
4712 <li>1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.IP6.ARPA</li>
4713 <li>D.F.IP6.ARPA</li>
4714 <li>8.E.F.IP6.ARPA</li>
4715 <li>9.E.F.IP6.ARPA</li>
4716 <li>A.E.F.IP6.ARPA</li>
4717 <li>B.E.F.IP6.ARPA</li>
4722 Empty zones are settable at the view level and only apply to
4723 views of class IN. Disabled empty zones are only inherited
4724 from options if there are no disabled empty zones specified
4725 at the view level. To override the options list of disabled
4726 zones, you can disable the root zone at the view level, for example:
4728 <pre class="programlisting">
4729 disable-empty-zone ".";
4734 If you are using the address ranges covered here, you should
4735 already have reverse zones covering the addresses you use.
4736 In practice this appears to not be the case with many queries
4737 being made to the infrastructure servers for names in these
4738 spaces. So many in fact that sacrificial servers were needed
4739 to be deployed to channel the query load away from the
4740 infrastructure servers.
4742 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
4743 <h3 class="title">Note</h3>
4744 The real parent servers for these zones should disable all
4745 empty zone under the parent zone they serve. For the real
4746 root servers, this is all built-in empty zones. This will
4747 enable them to return referrals to deeper in the tree.
4749 <div class="variablelist"><dl>
4750 <dt><span class="term"><span><strong class="command">empty-server</strong></span></span></dt>
4752 Specify what server name will appear in the returned
4753 SOA record for empty zones. If none is specified, then
4754 the zone's name will be used.
4756 <dt><span class="term"><span><strong class="command">empty-contact</strong></span></span></dt>
4758 Specify what contact name will appear in the returned
4759 SOA record for empty zones. If none is specified, then
4762 <dt><span class="term"><span><strong class="command">empty-zones-enable</strong></span></span></dt>
4764 Enable or disable all empty zones. By default, they
4767 <dt><span class="term"><span><strong class="command">disable-empty-zone</strong></span></span></dt>
4769 Disable individual empty zones. By default, none are
4770 disabled. This option can be specified multiple times.
4774 <div class="sect3" lang="en">
4775 <div class="titlepage"><div><div><h4 class="title">
4776 <a name="acache"></a>Additional Section Caching</h4></div></div></div>
4778 The additional section cache, also called <span><strong class="command">acache</strong></span>,
4779 is an internal cache to improve the response performance of BIND 9.
4780 When additional section caching is enabled, BIND 9 will
4781 cache an internal short-cut to the additional section content for
4783 Note that <span><strong class="command">acache</strong></span> is an internal caching
4784 mechanism of BIND 9, and is not related to the DNS caching
4788 Additional section caching does not change the
4789 response content (except the RRsets ordering of the additional
4790 section, see below), but can improve the response performance
4792 It is particularly effective when BIND 9 acts as an authoritative
4793 server for a zone that has many delegations with many glue RRs.
4796 In order to obtain the maximum performance improvement
4797 from additional section caching, setting
4798 <span><strong class="command">additional-from-cache</strong></span>
4799 to <span><strong class="command">no</strong></span> is recommended, since the current
4800 implementation of <span><strong class="command">acache</strong></span>
4801 does not short-cut of additional section information from the
4805 One obvious disadvantage of <span><strong class="command">acache</strong></span> is
4806 that it requires much more
4807 memory for the internal cached data.
4808 Thus, if the response performance does not matter and memory
4809 consumption is much more critical, the
4810 <span><strong class="command">acache</strong></span> mechanism can be
4811 disabled by setting <span><strong class="command">acache-enable</strong></span> to
4812 <span><strong class="command">no</strong></span>.
4813 It is also possible to specify the upper limit of memory
4815 for acache by using <span><strong class="command">max-acache-size</strong></span>.
4818 Additional section caching also has a minor effect on the
4819 RRset ordering in the additional section.
4820 Without <span><strong class="command">acache</strong></span>,
4821 <span><strong class="command">cyclic</strong></span> order is effective for the additional
4822 section as well as the answer and authority sections.
4823 However, additional section caching fixes the ordering when it
4824 first caches an RRset for the additional section, and the same
4825 ordering will be kept in succeeding responses, regardless of the
4826 setting of <span><strong class="command">rrset-order</strong></span>.
4827 The effect of this should be minor, however, since an
4828 RRset in the additional section
4829 typically only contains a small number of RRs (and in many cases
4830 it only contains a single RR), in which case the
4831 ordering does not matter much.
4834 The following is a summary of options related to
4835 <span><strong class="command">acache</strong></span>.
4837 <div class="variablelist"><dl>
4838 <dt><span class="term"><span><strong class="command">acache-enable</strong></span></span></dt>
4840 If <span><strong class="command">yes</strong></span>, additional section caching is
4841 enabled. The default value is <span><strong class="command">no</strong></span>.
4843 <dt><span class="term"><span><strong class="command">acache-cleaning-interval</strong></span></span></dt>
4845 The server will remove stale cache entries, based on an LRU
4847 algorithm, every <span><strong class="command">acache-cleaning-interval</strong></span> minutes.
4848 The default is 60 minutes.
4849 If set to 0, no periodic cleaning will occur.
4851 <dt><span class="term"><span><strong class="command">max-acache-size</strong></span></span></dt>
4853 The maximum amount of memory in bytes to use for the server's acache.
4854 When the amount of data in the acache reaches this limit,
4856 will clean more aggressively so that the limit is not
4858 In a server with multiple views, the limit applies
4860 acache of each view.
4861 The default is <code class="literal">16M</code>.
4866 <div class="sect2" lang="en">
4867 <div class="titlepage"><div><div><h3 class="title">
4868 <a name="server_statement_grammar"></a><span><strong class="command">server</strong></span> Statement Grammar</h3></div></div></div>
4869 <pre class="programlisting"><span><strong class="command">server</strong></span> <em class="replaceable"><code>ip_addr[/prefixlen]</code></em> {
4870 [<span class="optional"> bogus <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
4871 [<span class="optional"> provide-ixfr <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
4872 [<span class="optional"> request-ixfr <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
4873 [<span class="optional"> edns <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
4874 [<span class="optional"> edns-udp-size <em class="replaceable"><code>number</code></em> ; </span>]
4875 [<span class="optional"> max-udp-size <em class="replaceable"><code>number</code></em> ; </span>]
4876 [<span class="optional"> transfers <em class="replaceable"><code>number</code></em> ; </span>]
4877 [<span class="optional"> transfer-format <em class="replaceable"><code>( one-answer | many-answers )</code></em> ; ]</span>]
4878 [<span class="optional"> keys <em class="replaceable"><code>{ string ; [<span class="optional"> string ; [<span class="optional">...</span>]</span>] }</code></em> ; </span>]
4879 [<span class="optional"> transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
4880 [<span class="optional"> transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
4881 [<span class="optional"> notify-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
4882 [<span class="optional"> notify-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
4883 [<span class="optional"> query-source [<span class="optional"> address ( <em class="replaceable"><code>ip_addr</code></em> | <em class="replaceable"><code>*</code></em> ) </span>] [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>]; </span>]
4884 [<span class="optional"> query-source-v6 [<span class="optional"> address ( <em class="replaceable"><code>ip_addr</code></em> | <em class="replaceable"><code>*</code></em> ) </span>] [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>]; </span>]
4885 [<span class="optional"> use-queryport-pool <em class="replaceable"><code>yes_or_no</code></em>; </span>]
4886 [<span class="optional"> queryport-pool-ports <em class="replaceable"><code>number</code></em>; </span>]
4887 [<span class="optional"> queryport-pool-updateinterval <em class="replaceable"><code>number</code></em>; </span>]
4891 <div class="sect2" lang="en">
4892 <div class="titlepage"><div><div><h3 class="title">
4893 <a name="server_statement_definition_and_usage"></a><span><strong class="command">server</strong></span> Statement Definition and
4894 Usage</h3></div></div></div>
4896 The <span><strong class="command">server</strong></span> statement defines
4898 to be associated with a remote name server. If a prefix length is
4899 specified, then a range of servers is covered. Only the most
4901 server clause applies regardless of the order in
4902 <code class="filename">named.conf</code>.
4905 The <span><strong class="command">server</strong></span> statement can occur at
4906 the top level of the
4907 configuration file or inside a <span><strong class="command">view</strong></span>
4909 If a <span><strong class="command">view</strong></span> statement contains
4910 one or more <span><strong class="command">server</strong></span> statements, only
4912 apply to the view and any top-level ones are ignored.
4913 If a view contains no <span><strong class="command">server</strong></span>
4915 any top-level <span><strong class="command">server</strong></span> statements are
4920 If you discover that a remote server is giving out bad data,
4921 marking it as bogus will prevent further queries to it. The
4923 value of <span><strong class="command">bogus</strong></span> is <span><strong class="command">no</strong></span>.
4926 The <span><strong class="command">provide-ixfr</strong></span> clause determines
4928 the local server, acting as master, will respond with an
4930 zone transfer when the given remote server, a slave, requests it.
4931 If set to <span><strong class="command">yes</strong></span>, incremental transfer
4933 whenever possible. If set to <span><strong class="command">no</strong></span>,
4935 to the remote server will be non-incremental. If not set, the
4937 of the <span><strong class="command">provide-ixfr</strong></span> option in the
4939 global options block is used as a default.
4942 The <span><strong class="command">request-ixfr</strong></span> clause determines
4944 the local server, acting as a slave, will request incremental zone
4945 transfers from the given remote server, a master. If not set, the
4946 value of the <span><strong class="command">request-ixfr</strong></span> option in
4948 global options block is used as a default.
4951 IXFR requests to servers that do not support IXFR will
4953 fall back to AXFR. Therefore, there is no need to manually list
4954 which servers support IXFR and which ones do not; the global
4956 of <span><strong class="command">yes</strong></span> should always work.
4957 The purpose of the <span><strong class="command">provide-ixfr</strong></span> and
4958 <span><strong class="command">request-ixfr</strong></span> clauses is
4959 to make it possible to disable the use of IXFR even when both
4961 and slave claim to support it, for example if one of the servers
4962 is buggy and crashes or corrupts data when IXFR is used.
4965 The <span><strong class="command">edns</strong></span> clause determines whether
4966 the local server will attempt to use EDNS when communicating
4967 with the remote server. The default is <span><strong class="command">yes</strong></span>.
4970 The <span><strong class="command">edns-udp-size</strong></span> option sets the EDNS UDP size
4971 that is advertised by <span><strong class="command">named</strong></span> when querying the remote server.
4972 Valid values are 512 to 4096 bytes (values outside this range will be
4973 silently adjusted). This option is useful when you wish to
4974 advertises a different value to this server than the value you
4975 advertise globally, for example, when there is a firewall at the
4976 remote site that is blocking large replies.
4979 The <span><strong class="command">max-udp-size</strong></span> option sets the
4980 maximum EDNS UDP message size <span><strong class="command">named</strong></span> will send. Valid
4981 values are 512 to 4096 bytes (values outside this range will
4982 be silently adjusted). This option is useful when you
4983 know that there is a firewall that is blocking large
4984 replies from <span><strong class="command">named</strong></span>.
4987 The server supports two zone transfer methods. The first, <span><strong class="command">one-answer</strong></span>,
4988 uses one DNS message per resource record transferred. <span><strong class="command">many-answers</strong></span> packs
4989 as many resource records as possible into a message. <span><strong class="command">many-answers</strong></span> is
4990 more efficient, but is only known to be understood by <acronym class="acronym">BIND</acronym> 9, <acronym class="acronym">BIND</acronym>
4991 8.x, and patched versions of <acronym class="acronym">BIND</acronym>
4992 4.9.5. You can specify which method
4993 to use for a server with the <span><strong class="command">transfer-format</strong></span> option.
4994 If <span><strong class="command">transfer-format</strong></span> is not
4995 specified, the <span><strong class="command">transfer-format</strong></span>
4997 by the <span><strong class="command">options</strong></span> statement will be
5000 <p><span><strong class="command">transfers</strong></span>
5001 is used to limit the number of concurrent inbound zone
5002 transfers from the specified server. If no
5003 <span><strong class="command">transfers</strong></span> clause is specified, the
5004 limit is set according to the
5005 <span><strong class="command">transfers-per-ns</strong></span> option.
5008 The <span><strong class="command">keys</strong></span> clause identifies a
5009 <span><strong class="command">key_id</strong></span> defined by the <span><strong class="command">key</strong></span> statement,
5010 to be used for transaction security (TSIG, <a href="Bv9ARM.ch04.html#tsig" title="TSIG">the section called “TSIG”</a>)
5011 when talking to the remote server.
5012 When a request is sent to the remote server, a request signature
5013 will be generated using the key specified here and appended to the
5014 message. A request originating from the remote server is not
5016 to be signed by this key.
5019 Although the grammar of the <span><strong class="command">keys</strong></span>
5021 allows for multiple keys, only a single key per server is
5026 The <span><strong class="command">transfer-source</strong></span> and
5027 <span><strong class="command">transfer-source-v6</strong></span> clauses specify
5028 the IPv4 and IPv6 source
5029 address to be used for zone transfer with the remote server,
5031 For an IPv4 remote server, only <span><strong class="command">transfer-source</strong></span> can
5033 Similarly, for an IPv6 remote server, only
5034 <span><strong class="command">transfer-source-v6</strong></span> can be
5036 For more details, see the description of
5037 <span><strong class="command">transfer-source</strong></span> and
5038 <span><strong class="command">transfer-source-v6</strong></span> in
5039 <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5042 The <span><strong class="command">notify-source</strong></span> and
5043 <span><strong class="command">notify-source-v6</strong></span> clauses specify the
5044 IPv4 and IPv6 source address to be used for notify
5045 messages sent to remote servers, respectively. For an
5046 IPv4 remote server, only <span><strong class="command">notify-source</strong></span>
5047 can be specified. Similarly, for an IPv6 remote server,
5048 only <span><strong class="command">notify-source-v6</strong></span> can be specified.
5051 The <span><strong class="command">query-source</strong></span> and
5052 <span><strong class="command">query-source-v6</strong></span> clauses specify the
5053 IPv4 and IPv6 source address to be used for queries
5054 sent to remote servers, respectively. For an IPv4
5055 remote server, only <span><strong class="command">query-source</strong></span> can
5056 be specified. Similarly, for an IPv6 remote server,
5057 only <span><strong class="command">query-source-v6</strong></span> can be specified.
5060 <div class="sect2" lang="en">
5061 <div class="titlepage"><div><div><h3 class="title">
5062 <a name="statschannels"></a><span><strong class="command">statistics-channels</strong></span> Statement Grammar</h3></div></div></div>
5063 <pre class="programlisting"><span><strong class="command">statistics-channels</strong></span> {
5064 [ inet ( ip_addr | * ) [ port ip_port ] [allow { <em class="replaceable"><code> address_match_list </code></em> } ]; ]
5069 <div class="sect2" lang="en">
5070 <div class="titlepage"><div><div><h3 class="title">
5071 <a name="id2586877"></a><span><strong class="command">statistics-channels</strong></span> Statement Definition and
5072 Usage</h3></div></div></div>
5074 The <span><strong class="command">statistics-channels</strong></span> statement
5075 declares communication channels to be used by system
5076 administrators to get access to statistics information of
5080 This statement intends to be flexible to support multiple
5081 communication protocols in the future, but currently only
5082 HTTP access is supported.
5083 It requires that BIND 9 be compiled with libxml2;
5084 the <span><strong class="command">statistics-channels</strong></span> statement is
5085 still accepted even if it is built without the library,
5086 but any HTTP access will fail with an error.
5089 An <span><strong class="command">inet</strong></span> control channel is a TCP socket
5090 listening at the specified <span><strong class="command">ip_port</strong></span> on the
5091 specified <span><strong class="command">ip_addr</strong></span>, which can be an IPv4 or IPv6
5092 address. An <span><strong class="command">ip_addr</strong></span> of <code class="literal">*</code> (asterisk) is
5093 interpreted as the IPv4 wildcard address; connections will be
5094 accepted on any of the system's IPv4 addresses.
5095 To listen on the IPv6 wildcard address,
5096 use an <span><strong class="command">ip_addr</strong></span> of <code class="literal">::</code>.
5099 If no port is specified, port 80 is used for HTTP channels.
5100 The asterisk "<code class="literal">*</code>" cannot be used for
5101 <span><strong class="command">ip_port</strong></span>.
5104 The attempt of opening a statistics channel is
5105 restricted by the optional <span><strong class="command">allow</strong></span> clause.
5106 Connections to the statistics channel are permitted based on the
5107 <span><strong class="command">address_match_list</strong></span>.
5108 If no <span><strong class="command">allow</strong></span> clause is present,
5109 <span><strong class="command">named</strong></span> accepts connection
5110 attempts from any address; since the statistics may
5111 contain sensitive internal information, it is highly
5112 recommended to restrict the source of connection requests
5116 If no <span><strong class="command">statistics-channels</strong></span> statement is present,
5117 <span><strong class="command">named</strong></span> will not open any communication channels.
5120 <div class="sect2" lang="en">
5121 <div class="titlepage"><div><div><h3 class="title">
5122 <a name="id2586964"></a><span><strong class="command">trusted-keys</strong></span> Statement Grammar</h3></div></div></div>
5123 <pre class="programlisting"><span><strong class="command">trusted-keys</strong></span> {
5124 <em class="replaceable"><code>string</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ;
5125 [<span class="optional"> <em class="replaceable"><code>string</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ; [<span class="optional">...</span>]</span>]
5129 <div class="sect2" lang="en">
5130 <div class="titlepage"><div><div><h3 class="title">
5131 <a name="id2587083"></a><span><strong class="command">trusted-keys</strong></span> Statement Definition
5132 and Usage</h3></div></div></div>
5134 The <span><strong class="command">trusted-keys</strong></span> statement defines
5135 DNSSEC security roots. DNSSEC is described in <a href="Bv9ARM.ch04.html#DNSSEC" title="DNSSEC">the section called “DNSSEC”</a>. A security root is defined when the
5136 public key for a non-authoritative zone is known, but
5137 cannot be securely obtained through DNS, either because
5138 it is the DNS root zone or because its parent zone is
5139 unsigned. Once a key has been configured as a trusted
5140 key, it is treated as if it had been validated and
5141 proven secure. The resolver attempts DNSSEC validation
5142 on all DNS data in subdomains of a security root.
5145 All keys (and corresponding zones) listed in
5146 <span><strong class="command">trusted-keys</strong></span> are deemed to exist regardless
5147 of what parent zones say. Similarly for all keys listed in
5148 <span><strong class="command">trusted-keys</strong></span> only those keys are
5149 used to validate the DNSKEY RRset. The parent's DS RRset
5153 The <span><strong class="command">trusted-keys</strong></span> statement can contain
5154 multiple key entries, each consisting of the key's
5155 domain name, flags, protocol, algorithm, and the Base-64
5156 representation of the key data.
5157 Spaces, tabs, newlines and carriage returns are ignored
5158 in the key data, so the configuration may be split up into
5162 <div class="sect2" lang="en">
5163 <div class="titlepage"><div><div><h3 class="title">
5164 <a name="view_statement_grammar"></a><span><strong class="command">view</strong></span> Statement Grammar</h3></div></div></div>
5165 <pre class="programlisting"><span><strong class="command">view</strong></span> <em class="replaceable"><code>view_name</code></em>
5166 [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
5167 match-clients { <em class="replaceable"><code>address_match_list</code></em> };
5168 match-destinations { <em class="replaceable"><code>address_match_list</code></em> };
5169 match-recursive-only <em class="replaceable"><code>yes_or_no</code></em> ;
5170 [<span class="optional"> <em class="replaceable"><code>view_option</code></em>; ...</span>]
5171 [<span class="optional"> <em class="replaceable"><code>zone_statement</code></em>; ...</span>]
5175 <div class="sect2" lang="en">
5176 <div class="titlepage"><div><div><h3 class="title">
5177 <a name="id2587165"></a><span><strong class="command">view</strong></span> Statement Definition and Usage</h3></div></div></div>
5179 The <span><strong class="command">view</strong></span> statement is a powerful
5181 of <acronym class="acronym">BIND</acronym> 9 that lets a name server
5182 answer a DNS query differently
5183 depending on who is asking. It is particularly useful for
5185 split DNS setups without having to run multiple servers.
5188 Each <span><strong class="command">view</strong></span> statement defines a view
5190 DNS namespace that will be seen by a subset of clients. A client
5192 a view if its source IP address matches the
5193 <code class="varname">address_match_list</code> of the view's
5194 <span><strong class="command">match-clients</strong></span> clause and its
5195 destination IP address matches
5196 the <code class="varname">address_match_list</code> of the
5198 <span><strong class="command">match-destinations</strong></span> clause. If not
5200 <span><strong class="command">match-clients</strong></span> and <span><strong class="command">match-destinations</strong></span>
5201 default to matching all addresses. In addition to checking IP
5203 <span><strong class="command">match-clients</strong></span> and <span><strong class="command">match-destinations</strong></span>
5204 can also take <span><strong class="command">keys</strong></span> which provide an
5206 client to select the view. A view can also be specified
5207 as <span><strong class="command">match-recursive-only</strong></span>, which
5208 means that only recursive
5209 requests from matching clients will match that view.
5210 The order of the <span><strong class="command">view</strong></span> statements is
5212 a client request will be resolved in the context of the first
5213 <span><strong class="command">view</strong></span> that it matches.
5216 Zones defined within a <span><strong class="command">view</strong></span>
5218 only be accessible to clients that match the <span><strong class="command">view</strong></span>.
5219 By defining a zone of the same name in multiple views, different
5220 zone data can be given to different clients, for example,
5222 and "external" clients in a split DNS setup.
5225 Many of the options given in the <span><strong class="command">options</strong></span> statement
5226 can also be used within a <span><strong class="command">view</strong></span>
5228 apply only when resolving queries with that view. When no
5230 value is given, the value in the <span><strong class="command">options</strong></span> statement
5231 is used as a default. Also, zone options can have default values
5233 in the <span><strong class="command">view</strong></span> statement; these
5234 view-specific defaults
5235 take precedence over those in the <span><strong class="command">options</strong></span> statement.
5238 Views are class specific. If no class is given, class IN
5239 is assumed. Note that all non-IN views must contain a hint zone,
5240 since only the IN class has compiled-in default hints.
5243 If there are no <span><strong class="command">view</strong></span> statements in
5245 file, a default view that matches any client is automatically
5247 in class IN. Any <span><strong class="command">zone</strong></span> statements
5249 the top level of the configuration file are considered to be part
5251 this default view, and the <span><strong class="command">options</strong></span>
5253 apply to the default view. If any explicit <span><strong class="command">view</strong></span>
5254 statements are present, all <span><strong class="command">zone</strong></span>
5256 occur inside <span><strong class="command">view</strong></span> statements.
5259 Here is an example of a typical split DNS setup implemented
5260 using <span><strong class="command">view</strong></span> statements:
5262 <pre class="programlisting">view "internal" {
5263 // This should match our internal networks.
5264 match-clients { 10.0.0.0/8; };
5266 // Provide recursive service to internal clients only.
5269 // Provide a complete view of the example.com zone
5270 // including addresses of internal hosts.
5271 zone "example.com" {
5273 file "example-internal.db";
5278 // Match all clients not matched by the previous view.
5279 match-clients { any; };
5281 // Refuse recursive service to external clients.
5284 // Provide a restricted view of the example.com zone
5285 // containing only publicly accessible hosts.
5286 zone "example.com" {
5288 file "example-external.db";
5293 <div class="sect2" lang="en">
5294 <div class="titlepage"><div><div><h3 class="title">
5295 <a name="zone_statement_grammar"></a><span><strong class="command">zone</strong></span>
5296 Statement Grammar</h3></div></div></div>
5297 <pre class="programlisting"><span><strong class="command">zone</strong></span> <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
5299 [<span class="optional"> allow-query { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5300 [<span class="optional"> allow-query-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5301 [<span class="optional"> allow-transfer { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5302 [<span class="optional"> allow-update { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5303 [<span class="optional"> update-policy { <em class="replaceable"><code>update_policy_rule</code></em> [<span class="optional">...</span>] }; </span>]
5304 [<span class="optional"> also-notify { <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
5305 [<span class="optional"> check-names (<code class="constant">warn</code>|<code class="constant">fail</code>|<code class="constant">ignore</code>) ; </span>]
5306 [<span class="optional"> check-mx (<code class="constant">warn</code>|<code class="constant">fail</code>|<code class="constant">ignore</code>) ; </span>]
5307 [<span class="optional"> check-wildcard <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5308 [<span class="optional"> check-integrity <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5309 [<span class="optional"> dialup <em class="replaceable"><code>dialup_option</code></em> ; </span>]
5310 [<span class="optional"> file <em class="replaceable"><code>string</code></em> ; </span>]
5311 [<span class="optional"> masterfile-format (<code class="constant">text</code>|<code class="constant">raw</code>) ; </span>]
5312 [<span class="optional"> journal <em class="replaceable"><code>string</code></em> ; </span>]
5313 [<span class="optional"> max-journal-size <em class="replaceable"><code>size_spec</code></em>; </span>]
5314 [<span class="optional"> forward (<code class="constant">only</code>|<code class="constant">first</code>) ; </span>]
5315 [<span class="optional"> forwarders { [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
5316 [<span class="optional"> ixfr-base <em class="replaceable"><code>string</code></em> ; </span>]
5317 [<span class="optional"> ixfr-from-differences <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5318 [<span class="optional"> ixfr-tmp-file <em class="replaceable"><code>string</code></em> ; </span>]
5319 [<span class="optional"> maintain-ixfr-base <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5320 [<span class="optional"> max-ixfr-log-size <em class="replaceable"><code>number</code></em> ; </span>]
5321 [<span class="optional"> max-transfer-idle-out <em class="replaceable"><code>number</code></em> ; </span>]
5322 [<span class="optional"> max-transfer-time-out <em class="replaceable"><code>number</code></em> ; </span>]
5323 [<span class="optional"> notify <em class="replaceable"><code>yes_or_no</code></em> | <em class="replaceable"><code>explicit</code></em> | <em class="replaceable"><code>master-only</code></em> ; </span>]
5324 [<span class="optional"> notify-delay <em class="replaceable"><code>seconds</code></em> ; </span>]
5325 [<span class="optional"> notify-to-soa <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5326 [<span class="optional"> pubkey <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ; </span>]
5327 [<span class="optional"> notify-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5328 [<span class="optional"> notify-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5329 [<span class="optional"> zone-statistics <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5330 [<span class="optional"> sig-validity-interval <em class="replaceable"><code>number</code></em> [<span class="optional"><em class="replaceable"><code>number</code></em></span>] ; </span>]
5331 [<span class="optional"> sig-signing-nodes <em class="replaceable"><code>number</code></em> ; </span>]
5332 [<span class="optional"> sig-signing-signatures <em class="replaceable"><code>number</code></em> ; </span>]
5333 [<span class="optional"> sig-signing-type <em class="replaceable"><code>number</code></em> ; </span>]
5334 [<span class="optional"> database <em class="replaceable"><code>string</code></em> ; </span>]
5335 [<span class="optional"> min-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
5336 [<span class="optional"> max-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
5337 [<span class="optional"> min-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
5338 [<span class="optional"> max-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
5339 [<span class="optional"> key-directory <em class="replaceable"><code>path_name</code></em>; </span>]
5340 [<span class="optional"> zero-no-soa-ttl <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5343 zone <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
5345 [<span class="optional"> allow-notify { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5346 [<span class="optional"> allow-query { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5347 [<span class="optional"> allow-query-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5348 [<span class="optional"> allow-transfer { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5349 [<span class="optional"> allow-update-forwarding { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5350 [<span class="optional"> update-check-ksk <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5351 [<span class="optional"> try-tcp-refresh <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5352 [<span class="optional"> also-notify { <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
5353 [<span class="optional"> check-names (<code class="constant">warn</code>|<code class="constant">fail</code>|<code class="constant">ignore</code>) ; </span>]
5354 [<span class="optional"> dialup <em class="replaceable"><code>dialup_option</code></em> ; </span>]
5355 [<span class="optional"> file <em class="replaceable"><code>string</code></em> ; </span>]
5356 [<span class="optional"> masterfile-format (<code class="constant">text</code>|<code class="constant">raw</code>) ; </span>]
5357 [<span class="optional"> journal <em class="replaceable"><code>string</code></em> ; </span>]
5358 [<span class="optional"> max-journal-size <em class="replaceable"><code>size_spec</code></em>; </span>]
5359 [<span class="optional"> forward (<code class="constant">only</code>|<code class="constant">first</code>) ; </span>]
5360 [<span class="optional"> forwarders { [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
5361 [<span class="optional"> ixfr-base <em class="replaceable"><code>string</code></em> ; </span>]
5362 [<span class="optional"> ixfr-from-differences <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5363 [<span class="optional"> ixfr-tmp-file <em class="replaceable"><code>string</code></em> ; </span>]
5364 [<span class="optional"> maintain-ixfr-base <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5365 [<span class="optional"> masters [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] { ( <em class="replaceable"><code>masters_list</code></em> | <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] [<span class="optional">key <em class="replaceable"><code>key</code></em></span>] ) ; [<span class="optional">...</span>] }; </span>]
5366 [<span class="optional"> max-ixfr-log-size <em class="replaceable"><code>number</code></em> ; </span>]
5367 [<span class="optional"> max-transfer-idle-in <em class="replaceable"><code>number</code></em> ; </span>]
5368 [<span class="optional"> max-transfer-idle-out <em class="replaceable"><code>number</code></em> ; </span>]
5369 [<span class="optional"> max-transfer-time-in <em class="replaceable"><code>number</code></em> ; </span>]
5370 [<span class="optional"> max-transfer-time-out <em class="replaceable"><code>number</code></em> ; </span>]
5371 [<span class="optional"> notify <em class="replaceable"><code>yes_or_no</code></em> | <em class="replaceable"><code>explicit</code></em> | <em class="replaceable"><code>master-only</code></em> ; </span>]
5372 [<span class="optional"> notify-delay <em class="replaceable"><code>seconds</code></em> ; </span>]
5373 [<span class="optional"> notify-to-soa <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5374 [<span class="optional"> pubkey <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ; </span>]
5375 [<span class="optional"> transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5376 [<span class="optional"> transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5377 [<span class="optional"> alt-transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5378 [<span class="optional"> alt-transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5379 [<span class="optional"> use-alt-transfer-source <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5380 [<span class="optional"> notify-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5381 [<span class="optional"> notify-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5382 [<span class="optional"> zone-statistics <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5383 [<span class="optional"> database <em class="replaceable"><code>string</code></em> ; </span>]
5384 [<span class="optional"> min-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
5385 [<span class="optional"> max-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
5386 [<span class="optional"> min-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
5387 [<span class="optional"> max-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
5388 [<span class="optional"> multi-master <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5389 [<span class="optional"> zero-no-soa-ttl <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5392 zone <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
5394 file <em class="replaceable"><code>string</code></em> ;
5395 [<span class="optional"> delegation-only <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5396 [<span class="optional"> check-names (<code class="constant">warn</code>|<code class="constant">fail</code>|<code class="constant">ignore</code>) ; // Not Implemented. </span>]
5399 zone <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
5401 [<span class="optional"> allow-query { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5402 [<span class="optional"> allow-query-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5403 [<span class="optional"> check-names (<code class="constant">warn</code>|<code class="constant">fail</code>|<code class="constant">ignore</code>) ; </span>]
5404 [<span class="optional"> dialup <em class="replaceable"><code>dialup_option</code></em> ; </span>]
5405 [<span class="optional"> delegation-only <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5406 [<span class="optional"> file <em class="replaceable"><code>string</code></em> ; </span>]
5407 [<span class="optional"> masterfile-format (<code class="constant">text</code>|<code class="constant">raw</code>) ; </span>]
5408 [<span class="optional"> forward (<code class="constant">only</code>|<code class="constant">first</code>) ; </span>]
5409 [<span class="optional"> forwarders { [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
5410 [<span class="optional"> masters [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] { ( <em class="replaceable"><code>masters_list</code></em> | <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] [<span class="optional">key <em class="replaceable"><code>key</code></em></span>] ) ; [<span class="optional">...</span>] }; </span>]
5411 [<span class="optional"> max-transfer-idle-in <em class="replaceable"><code>number</code></em> ; </span>]
5412 [<span class="optional"> max-transfer-time-in <em class="replaceable"><code>number</code></em> ; </span>]
5413 [<span class="optional"> pubkey <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ; </span>]
5414 [<span class="optional"> transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5415 [<span class="optional"> transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5416 [<span class="optional"> alt-transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5417 [<span class="optional"> alt-transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5418 [<span class="optional"> use-alt-transfer-source <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5419 [<span class="optional"> zone-statistics <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5420 [<span class="optional"> database <em class="replaceable"><code>string</code></em> ; </span>]
5421 [<span class="optional"> min-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
5422 [<span class="optional"> max-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
5423 [<span class="optional"> min-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
5424 [<span class="optional"> max-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
5425 [<span class="optional"> multi-master <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5428 zone <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
5430 [<span class="optional"> forward (<code class="constant">only</code>|<code class="constant">first</code>) ; </span>]
5431 [<span class="optional"> forwarders { [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
5432 [<span class="optional"> delegation-only <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5435 zone <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
5436 type delegation-only;
5441 <div class="sect2" lang="en">
5442 <div class="titlepage"><div><div><h3 class="title">
5443 <a name="id2588638"></a><span><strong class="command">zone</strong></span> Statement Definition and Usage</h3></div></div></div>
5444 <div class="sect3" lang="en">
5445 <div class="titlepage"><div><div><h4 class="title">
5446 <a name="id2588646"></a>Zone Types</h4></div></div></div>
5447 <div class="informaltable"><table border="1">
5456 <code class="varname">master</code>
5461 The server has a master copy of the data
5462 for the zone and will be able to provide authoritative
5471 <code class="varname">slave</code>
5476 A slave zone is a replica of a master
5477 zone. The <span><strong class="command">masters</strong></span> list
5478 specifies one or more IP addresses
5479 of master servers that the slave contacts to update
5480 its copy of the zone.
5481 Masters list elements can also be names of other
5483 By default, transfers are made from port 53 on the
5485 be changed for all servers by specifying a port number
5487 list of IP addresses, or on a per-server basis after
5489 Authentication to the master can also be done with
5490 per-server TSIG keys.
5491 If a file is specified, then the
5492 replica will be written to this file whenever the zone
5494 and reloaded from this file on a server restart. Use
5496 recommended, since it often speeds server startup and
5498 a needless waste of bandwidth. Note that for large
5500 tens or hundreds of thousands) of zones per server, it
5502 use a two-level naming scheme for zone filenames. For
5504 a slave server for the zone <code class="literal">example.com</code> might place
5505 the zone contents into a file called
5506 <code class="filename">ex/example.com</code> where <code class="filename">ex/</code> is
5507 just the first two letters of the zone name. (Most
5509 behave very slowly if you put 100000 files into
5510 a single directory.)
5517 <code class="varname">stub</code>
5522 A stub zone is similar to a slave zone,
5523 except that it replicates only the NS records of a
5525 of the entire zone. Stub zones are not a standard part
5527 they are a feature specific to the <acronym class="acronym">BIND</acronym> implementation.
5531 Stub zones can be used to eliminate the need for glue
5533 in a parent zone at the expense of maintaining a stub
5535 a set of name server addresses in <code class="filename">named.conf</code>.
5536 This usage is not recommended for new configurations,
5538 supports it only in a limited way.
5539 In <acronym class="acronym">BIND</acronym> 4/8, zone
5540 transfers of a parent zone
5541 included the NS records from stub children of that
5543 that, in some cases, users could get away with
5544 configuring child stubs
5545 only in the master server for the parent zone. <acronym class="acronym">BIND</acronym>
5546 9 never mixes together zone data from different zones
5548 way. Therefore, if a <acronym class="acronym">BIND</acronym> 9 master serving a parent
5549 zone has child stub zones configured, all the slave
5551 parent zone also need to have the same child stub
5557 Stub zones can also be used as a way of forcing the
5559 of a given domain to use a particular set of
5560 authoritative servers.
5561 For example, the caching name servers on a private
5563 RFC1918 addressing may be configured with stub zones
5565 <code class="literal">10.in-addr.arpa</code>
5566 to use a set of internal name servers as the
5568 servers for that domain.
5575 <code class="varname">forward</code>
5580 A "forward zone" is a way to configure
5581 forwarding on a per-domain basis. A <span><strong class="command">zone</strong></span> statement
5582 of type <span><strong class="command">forward</strong></span> can
5583 contain a <span><strong class="command">forward</strong></span>
5584 and/or <span><strong class="command">forwarders</strong></span>
5586 which will apply to queries within the domain given by
5588 name. If no <span><strong class="command">forwarders</strong></span>
5589 statement is present or
5590 an empty list for <span><strong class="command">forwarders</strong></span> is given, then no
5591 forwarding will be done for the domain, canceling the
5593 any forwarders in the <span><strong class="command">options</strong></span> statement. Thus
5594 if you want to use this type of zone to change the
5596 global <span><strong class="command">forward</strong></span> option
5597 (that is, "forward first"
5598 to, then "forward only", or vice versa, but want to
5600 servers as set globally) you need to re-specify the
5608 <code class="varname">hint</code>
5613 The initial set of root name servers is
5614 specified using a "hint zone". When the server starts
5616 the root hints to find a root name server and get the
5618 list of root name servers. If no hint zone is
5620 IN, the server uses a compiled-in default set of root
5622 Classes other than IN have no built-in defaults hints.
5629 <code class="varname">delegation-only</code>
5634 This is used to enforce the delegation-only
5635 status of infrastructure zones (e.g. COM,
5636 NET, ORG). Any answer that is received
5637 without an explicit or implicit delegation
5638 in the authority section will be treated
5639 as NXDOMAIN. This does not apply to the
5640 zone apex. This should not be applied to
5644 <code class="varname">delegation-only</code> has no
5645 effect on answers received from forwarders.
5648 See caveats in <a href="Bv9ARM.ch06.html#root_delegation_only"><span><strong class="command">root-delegation-only</strong></span></a>.
5655 <div class="sect3" lang="en">
5656 <div class="titlepage"><div><div><h4 class="title">
5657 <a name="id2589005"></a>Class</h4></div></div></div>
5659 The zone's name may optionally be followed by a class. If
5660 a class is not specified, class <code class="literal">IN</code> (for <code class="varname">Internet</code>),
5661 is assumed. This is correct for the vast majority of cases.
5664 The <code class="literal">hesiod</code> class is
5665 named for an information service from MIT's Project Athena. It
5667 used to share information about various systems databases, such
5668 as users, groups, printers and so on. The keyword
5669 <code class="literal">HS</code> is
5670 a synonym for hesiod.
5673 Another MIT development is Chaosnet, a LAN protocol created
5674 in the mid-1970s. Zone data for it can be specified with the <code class="literal">CHAOS</code> class.
5677 <div class="sect3" lang="en">
5678 <div class="titlepage"><div><div><h4 class="title">
5679 <a name="id2589038"></a>Zone Options</h4></div></div></div>
5680 <div class="variablelist"><dl>
5681 <dt><span class="term"><span><strong class="command">allow-notify</strong></span></span></dt>
5683 See the description of
5684 <span><strong class="command">allow-notify</strong></span> in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
5686 <dt><span class="term"><span><strong class="command">allow-query</strong></span></span></dt>
5688 See the description of
5689 <span><strong class="command">allow-query</strong></span> in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
5691 <dt><span class="term"><span><strong class="command">allow-query-on</strong></span></span></dt>
5693 See the description of
5694 <span><strong class="command">allow-query-on</strong></span> in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
5696 <dt><span class="term"><span><strong class="command">allow-transfer</strong></span></span></dt>
5698 See the description of <span><strong class="command">allow-transfer</strong></span>
5699 in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
5701 <dt><span class="term"><span><strong class="command">allow-update</strong></span></span></dt>
5703 See the description of <span><strong class="command">allow-update</strong></span>
5704 in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
5706 <dt><span class="term"><span><strong class="command">update-policy</strong></span></span></dt>
5708 Specifies a "Simple Secure Update" policy. See
5709 <a href="Bv9ARM.ch06.html#dynamic_update_policies" title="Dynamic Update Policies">the section called “Dynamic Update Policies”</a>.
5711 <dt><span class="term"><span><strong class="command">allow-update-forwarding</strong></span></span></dt>
5713 See the description of <span><strong class="command">allow-update-forwarding</strong></span>
5714 in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
5716 <dt><span class="term"><span><strong class="command">also-notify</strong></span></span></dt>
5718 Only meaningful if <span><strong class="command">notify</strong></span>
5720 active for this zone. The set of machines that will
5722 <code class="literal">DNS NOTIFY</code> message
5723 for this zone is made up of all the listed name servers
5725 the primary master) for the zone plus any IP addresses
5727 with <span><strong class="command">also-notify</strong></span>. A port
5729 with each <span><strong class="command">also-notify</strong></span>
5730 address to send the notify
5731 messages to a port other than the default of 53.
5732 <span><strong class="command">also-notify</strong></span> is not
5733 meaningful for stub zones.
5734 The default is the empty list.
5736 <dt><span class="term"><span><strong class="command">check-names</strong></span></span></dt>
5738 This option is used to restrict the character set and
5740 certain domain names in master files and/or DNS responses
5742 network. The default varies according to zone type. For <span><strong class="command">master</strong></span> zones the default is <span><strong class="command">fail</strong></span>. For <span><strong class="command">slave</strong></span>
5743 zones the default is <span><strong class="command">warn</strong></span>.
5745 <dt><span class="term"><span><strong class="command">check-mx</strong></span></span></dt>
5747 See the description of
5748 <span><strong class="command">check-mx</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
5750 <dt><span class="term"><span><strong class="command">check-wildcard</strong></span></span></dt>
5752 See the description of
5753 <span><strong class="command">check-wildcard</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
5755 <dt><span class="term"><span><strong class="command">check-integrity</strong></span></span></dt>
5757 See the description of
5758 <span><strong class="command">check-integrity</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
5760 <dt><span class="term"><span><strong class="command">check-sibling</strong></span></span></dt>
5762 See the description of
5763 <span><strong class="command">check-sibling</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
5765 <dt><span class="term"><span><strong class="command">zero-no-soa-ttl</strong></span></span></dt>
5767 See the description of
5768 <span><strong class="command">zero-no-soa-ttl</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
5770 <dt><span class="term"><span><strong class="command">update-check-ksk</strong></span></span></dt>
5772 See the description of
5773 <span><strong class="command">update-check-ksk</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
5775 <dt><span class="term"><span><strong class="command">try-tcp-refresh</strong></span></span></dt>
5777 See the description of
5778 <span><strong class="command">try-tcp-refresh</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
5780 <dt><span class="term"><span><strong class="command">database</strong></span></span></dt>
5783 Specify the type of database to be used for storing the
5784 zone data. The string following the <span><strong class="command">database</strong></span> keyword
5785 is interpreted as a list of whitespace-delimited words.
5787 identifies the database type, and any subsequent words are
5789 as arguments to the database to be interpreted in a way
5791 to the database type.
5794 The default is <strong class="userinput"><code>"rbt"</code></strong>, BIND 9's
5796 red-black-tree database. This database does not take
5800 Other values are possible if additional database drivers
5801 have been linked into the server. Some sample drivers are
5803 with the distribution but none are linked in by default.
5806 <dt><span class="term"><span><strong class="command">dialup</strong></span></span></dt>
5808 See the description of
5809 <span><strong class="command">dialup</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
5811 <dt><span class="term"><span><strong class="command">delegation-only</strong></span></span></dt>
5814 The flag only applies to hint and stub zones. If set
5815 to <strong class="userinput"><code>yes</code></strong>, then the zone will also be
5816 treated as if it is also a delegation-only type zone.
5819 See caveats in <a href="Bv9ARM.ch06.html#root_delegation_only"><span><strong class="command">root-delegation-only</strong></span></a>.
5822 <dt><span class="term"><span><strong class="command">forward</strong></span></span></dt>
5824 Only meaningful if the zone has a forwarders
5825 list. The <span><strong class="command">only</strong></span> value causes
5827 after trying the forwarders and getting no answer, while <span><strong class="command">first</strong></span> would
5828 allow a normal lookup to be tried.
5830 <dt><span class="term"><span><strong class="command">forwarders</strong></span></span></dt>
5832 Used to override the list of global forwarders.
5833 If it is not specified in a zone of type <span><strong class="command">forward</strong></span>,
5834 no forwarding is done for the zone and the global options are
5837 <dt><span class="term"><span><strong class="command">ixfr-base</strong></span></span></dt>
5839 Was used in <acronym class="acronym">BIND</acronym> 8 to
5841 of the transaction log (journal) file for dynamic update
5843 <acronym class="acronym">BIND</acronym> 9 ignores the option
5844 and constructs the name of the journal
5845 file by appending "<code class="filename">.jnl</code>"
5849 <dt><span class="term"><span><strong class="command">ixfr-tmp-file</strong></span></span></dt>
5851 Was an undocumented option in <acronym class="acronym">BIND</acronym> 8.
5852 Ignored in <acronym class="acronym">BIND</acronym> 9.
5854 <dt><span class="term"><span><strong class="command">journal</strong></span></span></dt>
5856 Allow the default journal's filename to be overridden.
5857 The default is the zone's filename with "<code class="filename">.jnl</code>" appended.
5858 This is applicable to <span><strong class="command">master</strong></span> and <span><strong class="command">slave</strong></span> zones.
5860 <dt><span class="term"><span><strong class="command">max-journal-size</strong></span></span></dt>
5862 See the description of
5863 <span><strong class="command">max-journal-size</strong></span> in <a href="Bv9ARM.ch06.html#server_resource_limits" title="Server Resource Limits">the section called “Server Resource Limits”</a>.
5865 <dt><span class="term"><span><strong class="command">max-transfer-time-in</strong></span></span></dt>
5867 See the description of
5868 <span><strong class="command">max-transfer-time-in</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5870 <dt><span class="term"><span><strong class="command">max-transfer-idle-in</strong></span></span></dt>
5872 See the description of
5873 <span><strong class="command">max-transfer-idle-in</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5875 <dt><span class="term"><span><strong class="command">max-transfer-time-out</strong></span></span></dt>
5877 See the description of
5878 <span><strong class="command">max-transfer-time-out</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5880 <dt><span class="term"><span><strong class="command">max-transfer-idle-out</strong></span></span></dt>
5882 See the description of
5883 <span><strong class="command">max-transfer-idle-out</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5885 <dt><span class="term"><span><strong class="command">notify</strong></span></span></dt>
5887 See the description of
5888 <span><strong class="command">notify</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
5890 <dt><span class="term"><span><strong class="command">notify-delay</strong></span></span></dt>
5892 See the description of
5893 <span><strong class="command">notify-delay</strong></span> in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
5895 <dt><span class="term"><span><strong class="command">notify-to-soa</strong></span></span></dt>
5897 See the description of
5898 <span><strong class="command">notify-to-soa</strong></span> in
5899 <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
5901 <dt><span class="term"><span><strong class="command">pubkey</strong></span></span></dt>
5903 In <acronym class="acronym">BIND</acronym> 8, this option was
5904 intended for specifying
5905 a public zone key for verification of signatures in DNSSEC
5907 zones when they are loaded from disk. <acronym class="acronym">BIND</acronym> 9 does not verify signatures
5908 on load and ignores the option.
5910 <dt><span class="term"><span><strong class="command">zone-statistics</strong></span></span></dt>
5912 If <strong class="userinput"><code>yes</code></strong>, the server will keep
5914 information for this zone, which can be dumped to the
5915 <span><strong class="command">statistics-file</strong></span> defined in
5918 <dt><span class="term"><span><strong class="command">sig-validity-interval</strong></span></span></dt>
5920 See the description of
5921 <span><strong class="command">sig-validity-interval</strong></span> in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
5923 <dt><span class="term"><span><strong class="command">sig-signing-nodes</strong></span></span></dt>
5925 See the description of
5926 <span><strong class="command">sig-signing-nodes</strong></span> in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
5928 <dt><span class="term"><span><strong class="command">sig-signing-signatures</strong></span></span></dt>
5930 See the description of
5931 <span><strong class="command">sig-signing-signatures</strong></span> in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
5933 <dt><span class="term"><span><strong class="command">sig-signing-type</strong></span></span></dt>
5935 See the description of
5936 <span><strong class="command">sig-signing-type</strong></span> in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
5938 <dt><span class="term"><span><strong class="command">transfer-source</strong></span></span></dt>
5940 See the description of
5941 <span><strong class="command">transfer-source</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5943 <dt><span class="term"><span><strong class="command">transfer-source-v6</strong></span></span></dt>
5945 See the description of
5946 <span><strong class="command">transfer-source-v6</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5948 <dt><span class="term"><span><strong class="command">alt-transfer-source</strong></span></span></dt>
5950 See the description of
5951 <span><strong class="command">alt-transfer-source</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5953 <dt><span class="term"><span><strong class="command">alt-transfer-source-v6</strong></span></span></dt>
5955 See the description of
5956 <span><strong class="command">alt-transfer-source-v6</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5958 <dt><span class="term"><span><strong class="command">use-alt-transfer-source</strong></span></span></dt>
5960 See the description of
5961 <span><strong class="command">use-alt-transfer-source</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5963 <dt><span class="term"><span><strong class="command">notify-source</strong></span></span></dt>
5965 See the description of
5966 <span><strong class="command">notify-source</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5968 <dt><span class="term"><span><strong class="command">notify-source-v6</strong></span></span></dt>
5970 See the description of
5971 <span><strong class="command">notify-source-v6</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5974 <span class="term"><span><strong class="command">min-refresh-time</strong></span>, </span><span class="term"><span><strong class="command">max-refresh-time</strong></span>, </span><span class="term"><span><strong class="command">min-retry-time</strong></span>, </span><span class="term"><span><strong class="command">max-retry-time</strong></span></span>
5977 See the description in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
5979 <dt><span class="term"><span><strong class="command">ixfr-from-differences</strong></span></span></dt>
5981 See the description of
5982 <span><strong class="command">ixfr-from-differences</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
5983 (Note that the <span><strong class="command">ixfr-from-differences</strong></span>
5984 <strong class="userinput"><code>master</code></strong> and
5985 <strong class="userinput"><code>slave</code></strong> choices are not
5986 available at the zone level.)
5988 <dt><span class="term"><span><strong class="command">key-directory</strong></span></span></dt>
5990 See the description of
5991 <span><strong class="command">key-directory</strong></span> in <a href="Bv9ARM.ch06.html#options" title="options Statement Definition and
5992 Usage">the section called “<span><strong class="command">options</strong></span> Statement Definition and
5995 <dt><span class="term"><span><strong class="command">multi-master</strong></span></span></dt>
5997 See the description of <span><strong class="command">multi-master</strong></span> in
5998 <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6000 <dt><span class="term"><span><strong class="command">masterfile-format</strong></span></span></dt>
6002 See the description of <span><strong class="command">masterfile-format</strong></span>
6003 in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
6007 <div class="sect3" lang="en">
6008 <div class="titlepage"><div><div><h4 class="title">
6009 <a name="dynamic_update_policies"></a>Dynamic Update Policies</h4></div></div></div>
6010 <p><acronym class="acronym">BIND</acronym> 9 supports two alternative
6011 methods of granting clients the right to perform
6012 dynamic updates to a zone, configured by the
6013 <span><strong class="command">allow-update</strong></span> and
6014 <span><strong class="command">update-policy</strong></span> option, respectively.
6017 The <span><strong class="command">allow-update</strong></span> clause works the
6018 same way as in previous versions of <acronym class="acronym">BIND</acronym>.
6019 It grants given clients the permission to update any
6020 record of any name in the zone.
6023 The <span><strong class="command">update-policy</strong></span> clause is new
6024 in <acronym class="acronym">BIND</acronym> 9 and allows more fine-grained
6025 control over what updates are allowed. A set of rules
6026 is specified, where each rule either grants or denies
6027 permissions for one or more names to be updated by
6028 one or more identities. If the dynamic update request
6029 message is signed (that is, it includes either a TSIG
6030 or SIG(0) record), the identity of the signer can be
6034 Rules are specified in the <span><strong class="command">update-policy</strong></span>
6035 zone option, and are only meaningful for master zones.
6036 When the <span><strong class="command">update-policy</strong></span> statement
6037 is present, it is a configuration error for the
6038 <span><strong class="command">allow-update</strong></span> statement to be
6039 present. The <span><strong class="command">update-policy</strong></span> statement
6040 only examines the signer of a message; the source
6041 address is not relevant.
6044 This is how a rule definition looks:
6046 <pre class="programlisting">
6047 ( <span><strong class="command">grant</strong></span> | <span><strong class="command">deny</strong></span> ) <em class="replaceable"><code>identity</code></em> <em class="replaceable"><code>nametype</code></em> <em class="replaceable"><code>name</code></em> [<span class="optional"> <em class="replaceable"><code>types</code></em> </span>]
6050 Each rule grants or denies privileges. Once a message has
6051 successfully matched a rule, the operation is immediately
6053 or denied and no further rules are examined. A rule is matched
6054 when the signer matches the identity field, the name matches the
6055 name field in accordance with the nametype field, and the type
6057 the types specified in the type field.
6060 No signer is required for <em class="replaceable"><code>tcp-self</code></em>
6061 or <em class="replaceable"><code>6to4-self</code></em> however the standard
6062 reverse mapping / prefix conversion must match the identity
6066 The identity field specifies a name or a wildcard
6067 name. Normally, this is the name of the TSIG or
6068 SIG(0) key used to sign the update request. When a
6069 TKEY exchange has been used to create a shared secret,
6070 the identity of the shared secret is the same as the
6071 identity of the key used to authenticate the TKEY
6072 exchange. TKEY is also the negotiation method used
6073 by GSS-TSIG, which establishes an identity that is
6074 the Kerberos principal of the client, such as
6075 <strong class="userinput"><code>"user@host.domain"</code></strong>. When the
6076 <em class="replaceable"><code>identity</code></em> field specifies
6077 a wildcard name, it is subject to DNS wildcard
6078 expansion, so the rule will apply to multiple identities.
6079 The <em class="replaceable"><code>identity</code></em> field must
6080 contain a fully-qualified domain name.
6083 The <em class="replaceable"><code>nametype</code></em> field has 12
6085 <code class="varname">name</code>, <code class="varname">subdomain</code>,
6086 <code class="varname">wildcard</code>, <code class="varname">self</code>,
6087 <code class="varname">selfsub</code>, <code class="varname">selfwild</code>,
6088 <code class="varname">krb5-self</code>, <code class="varname">ms-self</code>,
6089 <code class="varname">krb5-subdomain</code>,
6090 <code class="varname">ms-subdomain</code>,
6091 <code class="varname">tcp-self</code> and <code class="varname">6to4-self</code>.
6093 <div class="informaltable"><table border="1">
6102 <code class="varname">name</code>
6107 Exact-match semantics. This rule matches
6108 when the name being updated is identical
6109 to the contents of the
6110 <em class="replaceable"><code>name</code></em> field.
6117 <code class="varname">subdomain</code>
6122 This rule matches when the name being updated
6123 is a subdomain of, or identical to, the
6124 contents of the <em class="replaceable"><code>name</code></em>
6132 <code class="varname">wildcard</code>
6137 The <em class="replaceable"><code>name</code></em> field
6138 is subject to DNS wildcard expansion, and
6139 this rule matches when the name being updated
6140 name is a valid expansion of the wildcard.
6147 <code class="varname">self</code>
6152 This rule matches when the name being updated
6153 matches the contents of the
6154 <em class="replaceable"><code>identity</code></em> field.
6155 The <em class="replaceable"><code>name</code></em> field
6156 is ignored, but should be the same as the
6157 <em class="replaceable"><code>identity</code></em> field.
6158 The <code class="varname">self</code> nametype is
6159 most useful when allowing using one key per
6160 name to update, where the key has the same
6161 name as the name to be updated. The
6162 <em class="replaceable"><code>identity</code></em> would
6163 be specified as <code class="constant">*</code> (an asterisk) in
6171 <code class="varname">selfsub</code>
6176 This rule is similar to <code class="varname">self</code>
6177 except that subdomains of <code class="varname">self</code>
6178 can also be updated.
6185 <code class="varname">selfwild</code>
6190 This rule is similar to <code class="varname">self</code>
6191 except that only subdomains of
6192 <code class="varname">self</code> can be updated.
6199 <code class="varname">tcp-self</code>
6204 Allow updates that have been sent via TCP and
6205 for which the standard mapping from the initiating
6206 IP address into the IN-ADDR.ARPA and IP6.ARPA
6207 namespaces match the name to be updated.
6209 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
6210 <h3 class="title">Note</h3>
6211 It is theoretically possible to spoof these TCP
6219 <code class="varname">6to4-self</code>
6224 Allow the 6to4 prefix to be update by any TCP
6225 conection from the 6to4 network or from the
6226 corresponding IPv4 address. This is intended
6227 to allow NS or DNAME RRsets to be added to the
6230 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
6231 <h3 class="title">Note</h3>
6232 It is theoretically possible to spoof these TCP
6240 In all cases, the <em class="replaceable"><code>name</code></em>
6242 specify a fully-qualified domain name.
6245 If no types are explicitly specified, this rule matches
6246 all types except RRSIG, NS, SOA, NSEC and NSEC3. Types
6247 may be specified by name, including "ANY" (ANY matches
6248 all types except NSEC and NSEC3, which can never be
6249 updated). Note that when an attempt is made to delete
6250 all records associated with a name, the rules are
6251 checked for each existing record type.
6256 <div class="sect1" lang="en">
6257 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
6258 <a name="id2591117"></a>Zone File</h2></div></div></div>
6259 <div class="sect2" lang="en">
6260 <div class="titlepage"><div><div><h3 class="title">
6261 <a name="types_of_resource_records_and_when_to_use_them"></a>Types of Resource Records and When to Use Them</h3></div></div></div>
6263 This section, largely borrowed from RFC 1034, describes the
6264 concept of a Resource Record (RR) and explains when each is used.
6265 Since the publication of RFC 1034, several new RRs have been
6267 and implemented in the DNS. These are also included.
6269 <div class="sect3" lang="en">
6270 <div class="titlepage"><div><div><h4 class="title">
6271 <a name="id2591204"></a>Resource Records</h4></div></div></div>
6273 A domain name identifies a node. Each node has a set of
6274 resource information, which may be empty. The set of resource
6275 information associated with a particular name is composed of
6276 separate RRs. The order of RRs in a set is not significant and
6277 need not be preserved by name servers, resolvers, or other
6278 parts of the DNS. However, sorting of multiple RRs is
6279 permitted for optimization purposes, for example, to specify
6280 that a particular nearby server be tried first. See <a href="Bv9ARM.ch06.html#the_sortlist_statement" title="The sortlist Statement">the section called “The <span><strong class="command">sortlist</strong></span> Statement”</a> and <a href="Bv9ARM.ch06.html#rrset_ordering" title="RRset Ordering">the section called “RRset Ordering”</a>.
6283 The components of a Resource Record are:
6285 <div class="informaltable"><table border="1">
6299 The domain name where the RR is found.
6311 An encoded 16-bit value that specifies
6312 the type of the resource record.
6324 The time-to-live of the RR. This field
6325 is a 32-bit integer in units of seconds, and is
6327 resolvers when they cache RRs. The TTL describes how
6329 be cached before it should be discarded.
6341 An encoded 16-bit value that identifies
6342 a protocol family or instance of a protocol.
6354 The resource data. The format of the
6355 data is type (and sometimes class) specific.
6362 The following are <span class="emphasis"><em>types</em></span> of valid RRs:
6364 <div class="informaltable"><table border="1">
6378 A host address. In the IN class, this is a
6379 32-bit IP address. Described in RFC 1035.
6391 IPv6 address. Described in RFC 1886.
6403 IPv6 address. This can be a partial
6404 address (a suffix) and an indirection to the name
6405 where the rest of the
6406 address (the prefix) can be found. Experimental.
6407 Described in RFC 2874.
6419 Location of AFS database servers.
6420 Experimental. Described in RFC 1183.
6432 Address prefix list. Experimental.
6433 Described in RFC 3123.
6445 Holds a digital certificate.
6446 Described in RFC 2538.
6458 Identifies the canonical name of an alias.
6459 Described in RFC 1035.
6471 Is used for identifying which DHCP client is
6472 associated with this name. Described in RFC 4701.
6484 Replaces the domain name specified with
6485 another name to be looked up, effectively aliasing an
6487 subtree of the domain name space rather than a single
6489 as in the case of the CNAME RR.
6490 Described in RFC 2672.
6502 Stores a public key associated with a signed
6503 DNS zone. Described in RFC 4034.
6515 Stores the hash of a public key associated with a
6516 signed DNS zone. Described in RFC 4034.
6528 Specifies the global position. Superseded by LOC.
6540 Identifies the CPU and OS used by a host.
6541 Described in RFC 1035.
6553 Provides a method for storing IPsec keying material in
6554 DNS. Described in RFC 4025.
6566 Representation of ISDN addresses.
6567 Experimental. Described in RFC 1183.
6579 Stores a public key associated with a
6580 DNS name. Used in original DNSSEC; replaced
6581 by DNSKEY in DNSSECbis, but still used with
6582 SIG(0). Described in RFCs 2535 and 2931.
6594 Identifies a key exchanger for this
6595 DNS name. Described in RFC 2230.
6607 For storing GPS info. Described in RFC 1876.
6620 Identifies a mail exchange for the domain with
6621 a 16-bit preference value (lower is better)
6622 followed by the host name of the mail exchange.
6623 Described in RFC 974, RFC 1035.
6635 Name authority pointer. Described in RFC 2915.
6647 A network service access point.
6648 Described in RFC 1706.
6660 The authoritative name server for the
6661 domain. Described in RFC 1035.
6673 Used in DNSSECbis to securely indicate that
6674 RRs with an owner name in a certain name interval do
6676 a zone and indicate what RR types are present for an
6678 Described in RFC 4034.
6690 Used in DNSSECbis to securely indicate that
6691 RRs with an owner name in a certain name
6692 interval do not exist in a zone and indicate
6693 what RR types are present for an existing
6694 name. NSEC3 differs from NSEC in that it
6695 prevents zone enumeration but is more
6696 computationally expensive on both the server
6697 and the client than NSEC. Described in RFC
6710 Used in DNSSECbis to tell the authoritative
6711 server which NSEC3 chains are available to use.
6712 Described in RFC 5155.
6724 Used in DNSSEC to securely indicate that
6725 RRs with an owner name in a certain name interval do
6727 a zone and indicate what RR types are present for an
6729 Used in original DNSSEC; replaced by NSEC in
6731 Described in RFC 2535.
6743 A pointer to another part of the domain
6744 name space. Described in RFC 1035.
6756 Provides mappings between RFC 822 and X.400
6757 addresses. Described in RFC 2163.
6769 Information on persons responsible
6770 for the domain. Experimental. Described in RFC 1183.
6782 Contains DNSSECbis signature data. Described
6795 Route-through binding for hosts that
6796 do not have their own direct wide area network
6798 Experimental. Described in RFC 1183.
6810 Contains DNSSEC signature data. Used in
6811 original DNSSEC; replaced by RRSIG in
6812 DNSSECbis, but still used for SIG(0).
6813 Described in RFCs 2535 and 2931.
6825 Identifies the start of a zone of authority.
6826 Described in RFC 1035.
6838 Contains the Sender Policy Framework information
6839 for a given email domain. Described in RFC 4408.
6851 Information about well known network
6852 services (replaces WKS). Described in RFC 2782.
6864 Provides a way to securely publish a secure shell key's
6865 fingerprint. Described in RFC 4255.
6877 Text records. Described in RFC 1035.
6889 Information about which well known
6890 network services, such as SMTP, that a domain
6891 supports. Historical.
6903 Representation of X.25 network addresses.
6904 Experimental. Described in RFC 1183.
6911 The following <span class="emphasis"><em>classes</em></span> of resource records
6912 are currently valid in the DNS:
6914 <div class="informaltable"><table border="1">
6940 Chaosnet, a LAN protocol created at MIT in the
6942 Rarely used for its historical purpose, but reused for
6944 built-in server information zones, e.g.,
6945 <code class="literal">version.bind</code>.
6957 Hesiod, an information service
6958 developed by MIT's Project Athena. It is used to share
6960 about various systems databases, such as users,
6969 The owner name is often implicit, rather than forming an
6971 part of the RR. For example, many name servers internally form
6973 or hash structures for the name space, and chain RRs off nodes.
6974 The remaining RR parts are the fixed header (type, class, TTL)
6975 which is consistent for all RRs, and a variable part (RDATA)
6977 fits the needs of the resource being described.
6980 The meaning of the TTL field is a time limit on how long an
6981 RR can be kept in a cache. This limit does not apply to
6983 data in zones; it is also timed out, but by the refreshing
6985 for the zone. The TTL is assigned by the administrator for the
6986 zone where the data originates. While short TTLs can be used to
6987 minimize caching, and a zero TTL prohibits caching, the
6989 of Internet performance suggest that these times should be on
6991 order of days for the typical host. If a change can be
6993 the TTL can be reduced prior to the change to minimize
6995 during the change, and then increased back to its former value
7000 The data in the RDATA section of RRs is carried as a combination
7001 of binary strings and domain names. The domain names are
7003 used as "pointers" to other data in the DNS.
7006 <div class="sect3" lang="en">
7007 <div class="titlepage"><div><div><h4 class="title">
7008 <a name="id2592759"></a>Textual expression of RRs</h4></div></div></div>
7010 RRs are represented in binary form in the packets of the DNS
7011 protocol, and are usually represented in highly encoded form
7013 stored in a name server or resolver. In the examples provided
7015 RFC 1034, a style similar to that used in master files was
7017 in order to show the contents of RRs. In this format, most RRs
7018 are shown on a single line, although continuation lines are
7023 The start of the line gives the owner of the RR. If a line
7024 begins with a blank, then the owner is assumed to be the same as
7025 that of the previous RR. Blank lines are often included for
7029 Following the owner, we list the TTL, type, and class of the
7030 RR. Class and type use the mnemonics defined above, and TTL is
7031 an integer before the type field. In order to avoid ambiguity
7033 parsing, type and class mnemonics are disjoint, TTLs are
7035 and the type mnemonic is always last. The IN class and TTL
7037 are often omitted from examples in the interests of clarity.
7040 The resource data or RDATA section of the RR are given using
7041 knowledge of the typical representation for the data.
7044 For example, we might show the RRs carried in a message as:
7046 <div class="informaltable"><table border="1">
7056 <code class="literal">ISI.EDU.</code>
7061 <code class="literal">MX</code>
7066 <code class="literal">10 VENERA.ISI.EDU.</code>
7076 <code class="literal">MX</code>
7081 <code class="literal">10 VAXA.ISI.EDU</code>
7088 <code class="literal">VENERA.ISI.EDU</code>
7093 <code class="literal">A</code>
7098 <code class="literal">128.9.0.32</code>
7108 <code class="literal">A</code>
7113 <code class="literal">10.1.0.52</code>
7120 <code class="literal">VAXA.ISI.EDU</code>
7125 <code class="literal">A</code>
7130 <code class="literal">10.2.0.27</code>
7140 <code class="literal">A</code>
7145 <code class="literal">128.9.0.33</code>
7152 The MX RRs have an RDATA section which consists of a 16-bit
7153 number followed by a domain name. The address RRs use a
7155 IP address format to contain a 32-bit internet address.
7158 The above example shows six RRs, with two RRs at each of three
7162 Similarly we might see:
7164 <div class="informaltable"><table border="1">
7174 <code class="literal">XX.LCS.MIT.EDU.</code>
7179 <code class="literal">IN A</code>
7184 <code class="literal">10.0.0.44</code>
7192 <code class="literal">CH A</code>
7197 <code class="literal">MIT.EDU. 2420</code>
7204 This example shows two addresses for
7205 <code class="literal">XX.LCS.MIT.EDU</code>, each of a different class.
7209 <div class="sect2" lang="en">
7210 <div class="titlepage"><div><div><h3 class="title">
7211 <a name="id2593348"></a>Discussion of MX Records</h3></div></div></div>
7213 As described above, domain servers store information as a
7214 series of resource records, each of which contains a particular
7215 piece of information about a given domain name (which is usually,
7216 but not always, a host). The simplest way to think of a RR is as
7217 a typed pair of data, a domain name matched with a relevant datum,
7218 and stored with some additional type information to help systems
7219 determine when the RR is relevant.
7222 MX records are used to control delivery of email. The data
7223 specified in the record is a priority and a domain name. The
7225 controls the order in which email delivery is attempted, with the
7226 lowest number first. If two priorities are the same, a server is
7227 chosen randomly. If no servers at a given priority are responding,
7228 the mail transport agent will fall back to the next largest
7230 Priority numbers do not have any absolute meaning — they are
7232 only respective to other MX records for that domain name. The
7234 name given is the machine to which the mail will be delivered.
7235 It <span class="emphasis"><em>must</em></span> have an associated address record
7236 (A or AAAA) — CNAME is not sufficient.
7239 For a given domain, if there is both a CNAME record and an
7240 MX record, the MX record is in error, and will be ignored.
7242 the mail will be delivered to the server specified in the MX
7244 pointed to by the CNAME.
7247 <div class="informaltable"><table border="1">
7259 <code class="literal">example.com.</code>
7264 <code class="literal">IN</code>
7269 <code class="literal">MX</code>
7274 <code class="literal">10</code>
7279 <code class="literal">mail.example.com.</code>
7289 <code class="literal">IN</code>
7294 <code class="literal">MX</code>
7299 <code class="literal">10</code>
7304 <code class="literal">mail2.example.com.</code>
7314 <code class="literal">IN</code>
7319 <code class="literal">MX</code>
7324 <code class="literal">20</code>
7329 <code class="literal">mail.backup.org.</code>
7336 <code class="literal">mail.example.com.</code>
7341 <code class="literal">IN</code>
7346 <code class="literal">A</code>
7351 <code class="literal">10.0.0.1</code>
7361 <code class="literal">mail2.example.com.</code>
7366 <code class="literal">IN</code>
7371 <code class="literal">A</code>
7376 <code class="literal">10.0.0.2</code>
7386 Mail delivery will be attempted to <code class="literal">mail.example.com</code> and
7387 <code class="literal">mail2.example.com</code> (in
7388 any order), and if neither of those succeed, delivery to <code class="literal">mail.backup.org</code> will
7392 <div class="sect2" lang="en">
7393 <div class="titlepage"><div><div><h3 class="title">
7394 <a name="Setting_TTLs"></a>Setting TTLs</h3></div></div></div>
7396 The time-to-live of the RR field is a 32-bit integer represented
7397 in units of seconds, and is primarily used by resolvers when they
7398 cache RRs. The TTL describes how long a RR can be cached before it
7399 should be discarded. The following three types of TTL are
7401 used in a zone file.
7403 <div class="informaltable"><table border="1">
7417 The last field in the SOA is the negative
7418 caching TTL. This controls how long other servers will
7419 cache no-such-domain
7420 (NXDOMAIN) responses from you.
7423 The maximum time for
7424 negative caching is 3 hours (3h).
7436 The $TTL directive at the top of the
7437 zone file (before the SOA) gives a default TTL for every
7451 Each RR can have a TTL as the second
7452 field in the RR, which will control how long other
7461 All of these TTLs default to units of seconds, though units
7462 can be explicitly specified, for example, <code class="literal">1h30m</code>.
7465 <div class="sect2" lang="en">
7466 <div class="titlepage"><div><div><h3 class="title">
7467 <a name="id2593895"></a>Inverse Mapping in IPv4</h3></div></div></div>
7469 Reverse name resolution (that is, translation from IP address
7470 to name) is achieved by means of the <span class="emphasis"><em>in-addr.arpa</em></span> domain
7471 and PTR records. Entries in the in-addr.arpa domain are made in
7472 least-to-most significant order, read left to right. This is the
7473 opposite order to the way IP addresses are usually written. Thus,
7474 a machine with an IP address of 10.1.2.3 would have a
7476 in-addr.arpa name of
7477 3.2.1.10.in-addr.arpa. This name should have a PTR resource record
7478 whose data field is the name of the machine or, optionally,
7480 PTR records if the machine has more than one name. For example,
7481 in the [<span class="optional">example.com</span>] domain:
7483 <div class="informaltable"><table border="1">
7492 <code class="literal">$ORIGIN</code>
7497 <code class="literal">2.1.10.in-addr.arpa</code>
7504 <code class="literal">3</code>
7509 <code class="literal">IN PTR foo.example.com.</code>
7515 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
7516 <h3 class="title">Note</h3>
7518 The <span><strong class="command">$ORIGIN</strong></span> lines in the examples
7519 are for providing context to the examples only — they do not
7521 appear in the actual usage. They are only used here to indicate
7522 that the example is relative to the listed origin.
7526 <div class="sect2" lang="en">
7527 <div class="titlepage"><div><div><h3 class="title">
7528 <a name="id2594090"></a>Other Zone File Directives</h3></div></div></div>
7530 The Master File Format was initially defined in RFC 1035 and
7531 has subsequently been extended. While the Master File Format
7533 is class independent all records in a Master File must be of the
7538 Master File Directives include <span><strong class="command">$ORIGIN</strong></span>, <span><strong class="command">$INCLUDE</strong></span>,
7539 and <span><strong class="command">$TTL.</strong></span>
7541 <div class="sect3" lang="en">
7542 <div class="titlepage"><div><div><h4 class="title">
7543 <a name="id2594113"></a>The <span><strong class="command">@</strong></span> (at-sign)</h4></div></div></div>
7545 When used in the label (or name) field, the asperand or
7546 at-sign (@) symbol represents the current origin.
7547 At the start of the zone file, it is the
7548 <<code class="varname">zone_name</code>> (followed by
7552 <div class="sect3" lang="en">
7553 <div class="titlepage"><div><div><h4 class="title">
7554 <a name="id2594129"></a>The <span><strong class="command">$ORIGIN</strong></span> Directive</h4></div></div></div>
7556 Syntax: <span><strong class="command">$ORIGIN</strong></span>
7557 <em class="replaceable"><code>domain-name</code></em>
7558 [<span class="optional"><em class="replaceable"><code>comment</code></em></span>]
7560 <p><span><strong class="command">$ORIGIN</strong></span>
7561 sets the domain name that will be appended to any
7562 unqualified records. When a zone is first read in there
7563 is an implicit <span><strong class="command">$ORIGIN</strong></span>
7564 <<code class="varname">zone_name</code>><span><strong class="command">.</strong></span>
7565 (followed by trailing dot).
7566 The current <span><strong class="command">$ORIGIN</strong></span> is appended to
7567 the domain specified in the <span><strong class="command">$ORIGIN</strong></span>
7568 argument if it is not absolute.
7570 <pre class="programlisting">
7571 $ORIGIN example.com.
7572 WWW CNAME MAIN-SERVER
7577 <pre class="programlisting">
7578 WWW.EXAMPLE.COM. CNAME MAIN-SERVER.EXAMPLE.COM.
7581 <div class="sect3" lang="en">
7582 <div class="titlepage"><div><div><h4 class="title">
7583 <a name="id2594326"></a>The <span><strong class="command">$INCLUDE</strong></span> Directive</h4></div></div></div>
7585 Syntax: <span><strong class="command">$INCLUDE</strong></span>
7586 <em class="replaceable"><code>filename</code></em>
7587 [<span class="optional">
7588 <em class="replaceable"><code>origin</code></em> </span>]
7589 [<span class="optional"> <em class="replaceable"><code>comment</code></em> </span>]
7592 Read and process the file <code class="filename">filename</code> as
7593 if it were included into the file at this point. If <span><strong class="command">origin</strong></span> is
7594 specified the file is processed with <span><strong class="command">$ORIGIN</strong></span> set
7595 to that value, otherwise the current <span><strong class="command">$ORIGIN</strong></span> is
7599 The origin and the current domain name
7600 revert to the values they had prior to the <span><strong class="command">$INCLUDE</strong></span> once
7601 the file has been read.
7603 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
7604 <h3 class="title">Note</h3>
7606 RFC 1035 specifies that the current origin should be restored
7608 an <span><strong class="command">$INCLUDE</strong></span>, but it is silent
7609 on whether the current
7610 domain name should also be restored. BIND 9 restores both of
7612 This could be construed as a deviation from RFC 1035, a
7617 <div class="sect3" lang="en">
7618 <div class="titlepage"><div><div><h4 class="title">
7619 <a name="id2594395"></a>The <span><strong class="command">$TTL</strong></span> Directive</h4></div></div></div>
7621 Syntax: <span><strong class="command">$TTL</strong></span>
7622 <em class="replaceable"><code>default-ttl</code></em>
7623 [<span class="optional">
7624 <em class="replaceable"><code>comment</code></em> </span>]
7627 Set the default Time To Live (TTL) for subsequent records
7628 with undefined TTLs. Valid TTLs are of the range 0-2147483647
7631 <p><span><strong class="command">$TTL</strong></span>
7632 is defined in RFC 2308.
7636 <div class="sect2" lang="en">
7637 <div class="titlepage"><div><div><h3 class="title">
7638 <a name="id2594500"></a><acronym class="acronym">BIND</acronym> Master File Extension: the <span><strong class="command">$GENERATE</strong></span> Directive</h3></div></div></div>
7640 Syntax: <span><strong class="command">$GENERATE</strong></span>
7641 <em class="replaceable"><code>range</code></em>
7642 <em class="replaceable"><code>lhs</code></em>
7643 [<span class="optional"><em class="replaceable"><code>ttl</code></em></span>]
7644 [<span class="optional"><em class="replaceable"><code>class</code></em></span>]
7645 <em class="replaceable"><code>type</code></em>
7646 <em class="replaceable"><code>rhs</code></em>
7647 [<span class="optional"><em class="replaceable"><code>comment</code></em></span>]
7649 <p><span><strong class="command">$GENERATE</strong></span>
7650 is used to create a series of resource records that only
7651 differ from each other by an
7652 iterator. <span><strong class="command">$GENERATE</strong></span> can be used to
7653 easily generate the sets of records required to support
7654 sub /24 reverse delegations described in RFC 2317:
7655 Classless IN-ADDR.ARPA delegation.
7657 <pre class="programlisting">$ORIGIN 0.0.192.IN-ADDR.ARPA.
7658 $GENERATE 1-2 0 NS SERVER$.EXAMPLE.
7659 $GENERATE 1-127 $ CNAME $.0</pre>
7663 <pre class="programlisting">0.0.0.192.IN-ADDR.ARPA. NS SERVER1.EXAMPLE.
7664 0.0.0.192.IN-ADDR.ARPA. NS SERVER2.EXAMPLE.
7665 1.0.0.192.IN-ADDR.ARPA. CNAME 1.0.0.0.192.IN-ADDR.ARPA.
7666 2.0.0.192.IN-ADDR.ARPA. CNAME 2.0.0.0.192.IN-ADDR.ARPA.
7668 127.0.0.192.IN-ADDR.ARPA. CNAME 127.0.0.0.192.IN-ADDR.ARPA.
7670 <div class="informaltable"><table border="1">
7678 <p><span><strong class="command">range</strong></span></p>
7682 This can be one of two forms: start-stop
7683 or start-stop/step. If the first form is used, then step
7685 1. All of start, stop and step must be positive.
7691 <p><span><strong class="command">lhs</strong></span></p>
7695 describes the owner name of the resource records
7696 to be created. Any single <span><strong class="command">$</strong></span>
7698 symbols within the <span><strong class="command">lhs</strong></span> string
7699 are replaced by the iterator value.
7701 To get a $ in the output, you need to escape the
7702 <span><strong class="command">$</strong></span> using a backslash
7703 <span><strong class="command">\</strong></span>,
7704 e.g. <span><strong class="command">\$</strong></span>. The
7705 <span><strong class="command">$</strong></span> may optionally be followed
7706 by modifiers which change the offset from the
7707 iterator, field width and base.
7709 Modifiers are introduced by a
7710 <span><strong class="command">{</strong></span> (left brace) immediately following the
7711 <span><strong class="command">$</strong></span> as
7712 <span><strong class="command">${offset[,width[,base]]}</strong></span>.
7713 For example, <span><strong class="command">${-20,3,d}</strong></span>
7714 subtracts 20 from the current value, prints the
7715 result as a decimal in a zero-padded field of
7718 Available output forms are decimal
7719 (<span><strong class="command">d</strong></span>), octal
7720 (<span><strong class="command">o</strong></span>) and hexadecimal
7721 (<span><strong class="command">x</strong></span> or <span><strong class="command">X</strong></span>
7722 for uppercase). The default modifier is
7723 <span><strong class="command">${0,0,d}</strong></span>. If the
7724 <span><strong class="command">lhs</strong></span> is not absolute, the
7725 current <span><strong class="command">$ORIGIN</strong></span> is appended
7729 For compatibility with earlier versions, <span><strong class="command">$$</strong></span> is still
7730 recognized as indicating a literal $ in the output.
7736 <p><span><strong class="command">ttl</strong></span></p>
7740 Specifies the time-to-live of the generated records. If
7741 not specified this will be inherited using the
7742 normal TTL inheritance rules.
7744 <p><span><strong class="command">class</strong></span>
7745 and <span><strong class="command">ttl</strong></span> can be
7746 entered in either order.
7752 <p><span><strong class="command">class</strong></span></p>
7756 Specifies the class of the generated records.
7757 This must match the zone class if it is
7760 <p><span><strong class="command">class</strong></span>
7761 and <span><strong class="command">ttl</strong></span> can be
7762 entered in either order.
7768 <p><span><strong class="command">type</strong></span></p>
7772 At present the only supported types are
7773 PTR, CNAME, DNAME, A, AAAA and NS.
7779 <p><span><strong class="command">rhs</strong></span></p>
7783 <span><strong class="command">rhs</strong></span> is a domain name. It is processed
7791 The <span><strong class="command">$GENERATE</strong></span> directive is a <acronym class="acronym">BIND</acronym> extension
7792 and not part of the standard zone file format.
7795 BIND 8 does not support the optional TTL and CLASS fields.
7798 <div class="sect2" lang="en">
7799 <div class="titlepage"><div><div><h3 class="title">
7800 <a name="zonefile_format"></a>Additional File Formats</h3></div></div></div>
7802 In addition to the standard textual format, BIND 9
7803 supports the ability to read or dump to zone files in
7804 other formats. The <code class="constant">raw</code> format is
7805 currently available as an additional format. It is a
7806 binary format representing BIND 9's internal data
7807 structure directly, thereby remarkably improving the
7811 For a primary server, a zone file in the
7812 <code class="constant">raw</code> format is expected to be
7813 generated from a textual zone file by the
7814 <span><strong class="command">named-compilezone</strong></span> command. For a
7815 secondary server or for a dynamic zone, it is automatically
7816 generated (if this format is specified by the
7817 <span><strong class="command">masterfile-format</strong></span> option) when
7818 <span><strong class="command">named</strong></span> dumps the zone contents after
7819 zone transfer or when applying prior updates.
7822 If a zone file in a binary format needs manual modification,
7823 it first must be converted to a textual form by the
7824 <span><strong class="command">named-compilezone</strong></span> command. All
7825 necessary modification should go to the text file, which
7826 should then be converted to the binary form by the
7827 <span><strong class="command">named-compilezone</strong></span> command again.
7830 Although the <code class="constant">raw</code> format uses the
7831 network byte order and avoids architecture-dependent
7832 data alignment so that it is as much portable as
7833 possible, it is primarily expected to be used inside
7834 the same single system. In order to export a zone
7835 file in the <code class="constant">raw</code> format or make a
7836 portable backup of the file, it is recommended to
7837 convert the file to the standard textual representation.
7841 <div class="sect1" lang="en">
7842 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
7843 <a name="statistics"></a>BIND9 Statistics</h2></div></div></div>
7845 <acronym class="acronym">BIND</acronym> 9 maintains lots of statistics
7846 information and provides several interfaces for users to
7847 get access to the statistics.
7848 The available statistics include all statistics counters
7849 that were available in <acronym class="acronym">BIND</acronym> 8 and
7850 are meaningful in <acronym class="acronym">BIND</acronym> 9,
7851 and other information that is considered useful.
7854 The statistics information is categorized into the following
7857 <div class="informaltable"><table border="1">
7865 <p>Incoming Requests</p>
7869 The number of incoming DNS requests for each OPCODE.
7875 <p>Incoming Queries</p>
7879 The number of incoming queries for each RR type.
7885 <p>Outgoing Queries</p>
7889 The number of outgoing queries for each RR
7890 type sent from the internal resolver.
7891 Maintained per view.
7897 <p>Name Server Statistics</p>
7901 Statistics counters about incoming request processing.
7907 <p>Zone Maintenance Statistics</p>
7911 Statistics counters regarding zone maintenance
7912 operations such as zone transfers.
7918 <p>Resolver Statistics</p>
7922 Statistics counters about name resolution
7923 performed in the internal resolver.
7924 Maintained per view.
7930 <p>Cache DB RRsets</p>
7934 The number of RRsets per RR type (positive
7935 or negative) and nonexistent names stored in the
7937 Maintained per view.
7943 <p>Socket I/O Statistics</p>
7947 Statistics counters about network related events.
7954 A subset of Name Server Statistics is collected and shown
7955 per zone for which the server has the authority when
7956 <span><strong class="command">zone-statistics</strong></span> is set to
7957 <strong class="userinput"><code>yes</code></strong>.
7958 These statistics counters are shown with their zone and view
7960 In some cases the view names are omitted for the default view.
7963 There are currently two user interfaces to get access to the
7965 One is in the plain text format dumped to the file specified
7966 by the <span><strong class="command">statistics-file</strong></span> configuration option.
7967 The other is remotely accessible via a statistics channel
7968 when the <span><strong class="command">statistics-channels</strong></span> statement
7969 is specified in the configuration file
7970 (see <a href="Bv9ARM.ch06.html#statschannels" title="statistics-channels Statement Grammar">the section called “<span><strong class="command">statistics-channels</strong></span> Statement Grammar”</a>.)
7972 <div class="sect3" lang="en">
7973 <div class="titlepage"><div><div><h4 class="title">
7974 <a name="statsfile"></a>The Statistics File</h4></div></div></div>
7976 The text format statistics dump begins with a line, like:
7979 <span><strong class="command">+++ Statistics Dump +++ (973798949)</strong></span>
7982 The number in parentheses is a standard
7983 Unix-style timestamp, measured as seconds since January 1, 1970.
7986 that line is a set of statistics information, which is categorized
7988 Each section begins with a line, like:
7991 <span><strong class="command">++ Name Server Statistics ++</strong></span>
7994 Each section consists of lines, each containing the statistics
7995 counter value followed by its textual description.
7996 See below for available counters.
7997 For brevity, counters that have a value of 0 are not shown
7998 in the statistics file.
8001 The statistics dump ends with the line where the
8002 number is identical to the number in the beginning line; for example:
8005 <span><strong class="command">--- Statistics Dump --- (973798949)</strong></span>
8008 <div class="sect2" lang="en">
8009 <div class="titlepage"><div><div><h3 class="title">
8010 <a name="statistics_counters"></a>Statistics Counters</h3></div></div></div>
8012 The following tables summarize statistics counters that
8013 <acronym class="acronym">BIND</acronym> 9 provides.
8014 For each row of the tables, the leftmost column is the
8015 abbreviated symbol name of that counter.
8016 These symbols are shown in the statistics information
8017 accessed via an HTTP statistics channel.
8018 The rightmost column gives the description of the counter,
8019 which is also shown in the statistics file
8020 (but, in this document, possibly with slight modification
8021 for better readability).
8022 Additional notes may also be provided in this column.
8023 When a middle column exists between these two columns,
8024 it gives the corresponding counter name of the
8025 <acronym class="acronym">BIND</acronym> 8 statistics, if applicable.
8027 <div class="sect3" lang="en">
8028 <div class="titlepage"><div><div><h4 class="title">
8029 <a name="id2595428"></a>Name Server Statistics Counters</h4></div></div></div>
8030 <div class="informaltable"><table border="1">
8040 <span class="emphasis"><em>Symbol</em></span>
8045 <span class="emphasis"><em>BIND8 Symbol</em></span>
8050 <span class="emphasis"><em>Description</em></span>
8056 <p><span><strong class="command">Requestv4</strong></span></p>
8059 <p><span><strong class="command">RQ</strong></span></p>
8063 IPv4 requests received.
8064 Note: this also counts non query requests.
8070 <p><span><strong class="command">Requestv6</strong></span></p>
8073 <p><span><strong class="command">RQ</strong></span></p>
8077 IPv6 requests received.
8078 Note: this also counts non query requests.
8084 <p><span><strong class="command">ReqEdns0</strong></span></p>
8087 <p><span><strong class="command"></strong></span></p>
8091 Requests with EDNS(0) received.
8097 <p><span><strong class="command">ReqBadEDNSVer</strong></span></p>
8100 <p><span><strong class="command"></strong></span></p>
8104 Requests with unsupported EDNS version received.
8110 <p><span><strong class="command">ReqTSIG</strong></span></p>
8113 <p><span><strong class="command"></strong></span></p>
8117 Requests with TSIG received.
8123 <p><span><strong class="command">ReqSIG0</strong></span></p>
8126 <p><span><strong class="command"></strong></span></p>
8130 Requests with SIG(0) received.
8136 <p><span><strong class="command">ReqBadSIG</strong></span></p>
8139 <p><span><strong class="command"></strong></span></p>
8143 Requests with invalid (TSIG or SIG(0)) signature.
8149 <p><span><strong class="command">ReqTCP</strong></span></p>
8152 <p><span><strong class="command">RTCP</strong></span></p>
8156 TCP requests received.
8162 <p><span><strong class="command">AuthQryRej</strong></span></p>
8165 <p><span><strong class="command">RUQ</strong></span></p>
8169 Authoritative (non recursive) queries rejected.
8175 <p><span><strong class="command">RecQryRej</strong></span></p>
8178 <p><span><strong class="command">RURQ</strong></span></p>
8182 Recursive queries rejected.
8188 <p><span><strong class="command">XfrRej</strong></span></p>
8191 <p><span><strong class="command">RUXFR</strong></span></p>
8195 Zone transfer requests rejected.
8201 <p><span><strong class="command">UpdateRej</strong></span></p>
8204 <p><span><strong class="command">RUUpd</strong></span></p>
8208 Dynamic update requests rejected.
8214 <p><span><strong class="command">Response</strong></span></p>
8217 <p><span><strong class="command">SAns</strong></span></p>
8227 <p><span><strong class="command">RespTruncated</strong></span></p>
8230 <p><span><strong class="command"></strong></span></p>
8234 Truncated responses sent.
8240 <p><span><strong class="command">RespEDNS0</strong></span></p>
8243 <p><span><strong class="command"></strong></span></p>
8247 Responses with EDNS(0) sent.
8253 <p><span><strong class="command">RespTSIG</strong></span></p>
8256 <p><span><strong class="command"></strong></span></p>
8260 Responses with TSIG sent.
8266 <p><span><strong class="command">RespSIG0</strong></span></p>
8269 <p><span><strong class="command"></strong></span></p>
8273 Responses with SIG(0) sent.
8279 <p><span><strong class="command">QrySuccess</strong></span></p>
8282 <p><span><strong class="command"></strong></span></p>
8286 Queries resulted in a successful answer.
8287 This means the query which returns a NOERROR response
8288 with at least one answer RR.
8289 This corresponds to the
8290 <span><strong class="command">success</strong></span> counter
8291 of previous versions of
8292 <acronym class="acronym">BIND</acronym> 9.
8298 <p><span><strong class="command">QryAuthAns</strong></span></p>
8301 <p><span><strong class="command"></strong></span></p>
8305 Queries resulted in authoritative answer.
8311 <p><span><strong class="command">QryNoauthAns</strong></span></p>
8314 <p><span><strong class="command">SNaAns</strong></span></p>
8318 Queries resulted in non authoritative answer.
8324 <p><span><strong class="command">QryReferral</strong></span></p>
8327 <p><span><strong class="command"></strong></span></p>
8331 Queries resulted in referral answer.
8332 This corresponds to the
8333 <span><strong class="command">referral</strong></span> counter
8334 of previous versions of
8335 <acronym class="acronym">BIND</acronym> 9.
8341 <p><span><strong class="command">QryNxrrset</strong></span></p>
8344 <p><span><strong class="command"></strong></span></p>
8348 Queries resulted in NOERROR responses with no data.
8349 This corresponds to the
8350 <span><strong class="command">nxrrset</strong></span> counter
8351 of previous versions of
8352 <acronym class="acronym">BIND</acronym> 9.
8358 <p><span><strong class="command">QrySERVFAIL</strong></span></p>
8361 <p><span><strong class="command">SFail</strong></span></p>
8365 Queries resulted in SERVFAIL.
8371 <p><span><strong class="command">QryFORMERR</strong></span></p>
8374 <p><span><strong class="command">SFErr</strong></span></p>
8378 Queries resulted in FORMERR.
8384 <p><span><strong class="command">QryNXDOMAIN</strong></span></p>
8387 <p><span><strong class="command">SNXD</strong></span></p>
8391 Queries resulted in NXDOMAIN.
8392 This corresponds to the
8393 <span><strong class="command">nxdomain</strong></span> counter
8394 of previous versions of
8395 <acronym class="acronym">BIND</acronym> 9.
8401 <p><span><strong class="command">QryRecursion</strong></span></p>
8404 <p><span><strong class="command">RFwdQ</strong></span></p>
8408 Queries which caused the server
8409 to perform recursion in order to find the final answer.
8410 This corresponds to the
8411 <span><strong class="command">recursion</strong></span> counter
8412 of previous versions of
8413 <acronym class="acronym">BIND</acronym> 9.
8419 <p><span><strong class="command">QryDuplicate</strong></span></p>
8422 <p><span><strong class="command">RDupQ</strong></span></p>
8426 Queries which the server attempted to
8427 recurse but discovered an existing query with the same
8428 IP address, port, query ID, name, type and class
8429 already being processed.
8430 This corresponds to the
8431 <span><strong class="command">duplicate</strong></span> counter
8432 of previous versions of
8433 <acronym class="acronym">BIND</acronym> 9.
8439 <p><span><strong class="command">QryDropped</strong></span></p>
8442 <p><span><strong class="command"></strong></span></p>
8446 Recursive queries for which the server
8447 discovered an excessive number of existing
8448 recursive queries for the same name, type and
8449 class and were subsequently dropped.
8450 This is the number of dropped queries due to
8451 the reason explained with the
8452 <span><strong class="command">clients-per-query</strong></span>
8454 <span><strong class="command">max-clients-per-query</strong></span>
8456 (see the description about
8457 <a href="Bv9ARM.ch06.html#clients-per-query"><span><strong class="command">clients-per-query</strong></span></a>.)
8458 This corresponds to the
8459 <span><strong class="command">dropped</strong></span> counter
8460 of previous versions of
8461 <acronym class="acronym">BIND</acronym> 9.
8467 <p><span><strong class="command">QryFailure</strong></span></p>
8470 <p><span><strong class="command"></strong></span></p>
8474 Other query failures.
8475 This corresponds to the
8476 <span><strong class="command">failure</strong></span> counter
8477 of previous versions of
8478 <acronym class="acronym">BIND</acronym> 9.
8479 Note: this counter is provided mainly for
8480 backward compatibility with the previous versions.
8481 Normally a more fine-grained counters such as
8482 <span><strong class="command">AuthQryRej</strong></span> and
8483 <span><strong class="command">RecQryRej</strong></span>
8484 that would also fall into this counter are provided,
8485 and so this counter would not be of much
8486 interest in practice.
8492 <p><span><strong class="command">XfrReqDone</strong></span></p>
8495 <p><span><strong class="command"></strong></span></p>
8499 Requested zone transfers completed.
8505 <p><span><strong class="command">UpdateReqFwd</strong></span></p>
8508 <p><span><strong class="command"></strong></span></p>
8512 Update requests forwarded.
8518 <p><span><strong class="command">UpdateRespFwd</strong></span></p>
8521 <p><span><strong class="command"></strong></span></p>
8525 Update responses forwarded.
8531 <p><span><strong class="command">UpdateFwdFail</strong></span></p>
8534 <p><span><strong class="command"></strong></span></p>
8538 Dynamic update forward failed.
8544 <p><span><strong class="command">UpdateDone</strong></span></p>
8547 <p><span><strong class="command"></strong></span></p>
8551 Dynamic updates completed.
8557 <p><span><strong class="command">UpdateFail</strong></span></p>
8560 <p><span><strong class="command"></strong></span></p>
8564 Dynamic updates failed.
8570 <p><span><strong class="command">UpdateBadPrereq</strong></span></p>
8573 <p><span><strong class="command"></strong></span></p>
8577 Dynamic updates rejected due to prerequisite failure.
8584 <div class="sect3" lang="en">
8585 <div class="titlepage"><div><div><h4 class="title">
8586 <a name="id2596901"></a>Zone Maintenance Statistics Counters</h4></div></div></div>
8587 <div class="informaltable"><table border="1">
8596 <span class="emphasis"><em>Symbol</em></span>
8601 <span class="emphasis"><em>Description</em></span>
8607 <p><span><strong class="command">NotifyOutv4</strong></span></p>
8617 <p><span><strong class="command">NotifyOutv6</strong></span></p>
8627 <p><span><strong class="command">NotifyInv4</strong></span></p>
8631 IPv4 notifies received.
8637 <p><span><strong class="command">NotifyInv6</strong></span></p>
8641 IPv6 notifies received.
8647 <p><span><strong class="command">NotifyRej</strong></span></p>
8651 Incoming notifies rejected.
8657 <p><span><strong class="command">SOAOutv4</strong></span></p>
8661 IPv4 SOA queries sent.
8667 <p><span><strong class="command">SOAOutv6</strong></span></p>
8671 IPv6 SOA queries sent.
8677 <p><span><strong class="command">AXFRReqv4</strong></span></p>
8681 IPv4 AXFR requested.
8687 <p><span><strong class="command">AXFRReqv6</strong></span></p>
8691 IPv6 AXFR requested.
8697 <p><span><strong class="command">IXFRReqv4</strong></span></p>
8701 IPv4 IXFR requested.
8707 <p><span><strong class="command">IXFRReqv6</strong></span></p>
8711 IPv6 IXFR requested.
8717 <p><span><strong class="command">XfrSuccess</strong></span></p>
8721 Zone transfer requests succeeded.
8727 <p><span><strong class="command">XfrFail</strong></span></p>
8731 Zone transfer requests failed.
8738 <div class="sect3" lang="en">
8739 <div class="titlepage"><div><div><h4 class="title">
8740 <a name="id2597284"></a>Resolver Statistics Counters</h4></div></div></div>
8741 <div class="informaltable"><table border="1">
8751 <span class="emphasis"><em>Symbol</em></span>
8756 <span class="emphasis"><em>BIND8 Symbol</em></span>
8761 <span class="emphasis"><em>Description</em></span>
8767 <p><span><strong class="command">Queryv4</strong></span></p>
8770 <p><span><strong class="command">SFwdQ</strong></span></p>
8780 <p><span><strong class="command">Queryv6</strong></span></p>
8783 <p><span><strong class="command">SFwdQ</strong></span></p>
8793 <p><span><strong class="command">Responsev4</strong></span></p>
8796 <p><span><strong class="command">RR</strong></span></p>
8800 IPv4 responses received.
8806 <p><span><strong class="command">Responsev6</strong></span></p>
8809 <p><span><strong class="command">RR</strong></span></p>
8813 IPv6 responses received.
8819 <p><span><strong class="command">NXDOMAIN</strong></span></p>
8822 <p><span><strong class="command">RNXD</strong></span></p>
8832 <p><span><strong class="command">SERVFAIL</strong></span></p>
8835 <p><span><strong class="command">RFail</strong></span></p>
8845 <p><span><strong class="command">FORMERR</strong></span></p>
8848 <p><span><strong class="command">RFErr</strong></span></p>
8858 <p><span><strong class="command">OtherError</strong></span></p>
8861 <p><span><strong class="command">RErr</strong></span></p>
8865 Other errors received.
8871 <p><span><strong class="command">EDNS0Fail</strong></span></p>
8874 <p><span><strong class="command"></strong></span></p>
8878 EDNS(0) query failures.
8884 <p><span><strong class="command">Mismatch</strong></span></p>
8887 <p><span><strong class="command">RDupR</strong></span></p>
8891 Mismatch responses received.
8897 <p><span><strong class="command">Truncated</strong></span></p>
8900 <p><span><strong class="command"></strong></span></p>
8904 Truncated responses received.
8910 <p><span><strong class="command">Lame</strong></span></p>
8913 <p><span><strong class="command">RLame</strong></span></p>
8917 Lame delegations received.
8923 <p><span><strong class="command">Retry</strong></span></p>
8926 <p><span><strong class="command">SDupQ</strong></span></p>
8930 Query retries performed.
8936 <p><span><strong class="command">QueryAbort</strong></span></p>
8939 <p><span><strong class="command"></strong></span></p>
8943 Queries aborted due to quota control.
8949 <p><span><strong class="command">QuerySockFail</strong></span></p>
8952 <p><span><strong class="command"></strong></span></p>
8956 Failures in opening query sockets.
8957 One common reason for such failures is a
8958 failure of opening a new socket due to a
8959 limitation on file descriptors.
8965 <p><span><strong class="command">QueryTimeout</strong></span></p>
8968 <p><span><strong class="command"></strong></span></p>
8978 <p><span><strong class="command">GlueFetchv4</strong></span></p>
8981 <p><span><strong class="command">SSysQ</strong></span></p>
8985 IPv4 NS address fetches invoked.
8991 <p><span><strong class="command">GlueFetchv6</strong></span></p>
8994 <p><span><strong class="command">SSysQ</strong></span></p>
8998 IPv6 NS address fetches invoked.
9004 <p><span><strong class="command">GlueFetchv4Fail</strong></span></p>
9007 <p><span><strong class="command"></strong></span></p>
9011 IPv4 NS address fetch failed.
9017 <p><span><strong class="command">GlueFetchv6Fail</strong></span></p>
9020 <p><span><strong class="command"></strong></span></p>
9024 IPv6 NS address fetch failed.
9030 <p><span><strong class="command">ValAttempt</strong></span></p>
9033 <p><span><strong class="command"></strong></span></p>
9037 DNSSEC validation attempted.
9043 <p><span><strong class="command">ValOk</strong></span></p>
9046 <p><span><strong class="command"></strong></span></p>
9050 DNSSEC validation succeeded.
9056 <p><span><strong class="command">ValNegOk</strong></span></p>
9059 <p><span><strong class="command"></strong></span></p>
9063 DNSSEC validation on negative information succeeded.
9069 <p><span><strong class="command">ValFail</strong></span></p>
9072 <p><span><strong class="command"></strong></span></p>
9076 DNSSEC validation failed.
9082 <p><span><strong class="command">QryRTTnn</strong></span></p>
9085 <p><span><strong class="command"></strong></span></p>
9089 Frequency table on round trip times (RTTs) of
9091 Each <span><strong class="command">nn</strong></span> specifies the corresponding
9094 <span><strong class="command">nn_1</strong></span>,
9095 <span><strong class="command">nn_2</strong></span>,
9097 <span><strong class="command">nn_m</strong></span>,
9098 the value of <span><strong class="command">nn_i</strong></span> is the
9099 number of queries whose RTTs are between
9100 <span><strong class="command">nn_(i-1)</strong></span> (inclusive) and
9101 <span><strong class="command">nn_i</strong></span> (exclusive) milliseconds.
9102 For the sake of convenience we define
9103 <span><strong class="command">nn_0</strong></span> to be 0.
9104 The last entry should be represented as
9105 <span><strong class="command">nn_m+</strong></span>, which means the
9106 number of queries whose RTTs are equal to or over
9107 <span><strong class="command">nn_m</strong></span> milliseconds.
9114 <div class="sect3" lang="en">
9115 <div class="titlepage"><div><div><h4 class="title">
9116 <a name="id2598302"></a>Socket I/O Statistics Counters</h4></div></div></div>
9118 Socket I/O statistics counters are defined per socket
9120 <span><strong class="command">UDP4</strong></span> (UDP/IPv4),
9121 <span><strong class="command">UDP6</strong></span> (UDP/IPv6),
9122 <span><strong class="command">TCP4</strong></span> (TCP/IPv4),
9123 <span><strong class="command">TCP6</strong></span> (TCP/IPv6),
9124 <span><strong class="command">Unix</strong></span> (Unix Domain), and
9125 <span><strong class="command">FDwatch</strong></span> (sockets opened outside the
9127 In the following table <span><strong class="command"><TYPE></strong></span>
9128 represents a socket type.
9129 Not all counters are available for all socket types;
9130 exceptions are noted in the description field.
9132 <div class="informaltable"><table border="1">
9141 <span class="emphasis"><em>Symbol</em></span>
9146 <span class="emphasis"><em>Description</em></span>
9152 <p><span><strong class="command"><TYPE>Open</strong></span></p>
9156 Sockets opened successfully.
9157 This counter is not applicable to the
9158 <span><strong class="command">FDwatch</strong></span> type.
9164 <p><span><strong class="command"><TYPE>OpenFail</strong></span></p>
9168 Failures of opening sockets.
9169 This counter is not applicable to the
9170 <span><strong class="command">FDwatch</strong></span> type.
9176 <p><span><strong class="command"><TYPE>Close</strong></span></p>
9186 <p><span><strong class="command"><TYPE>BindFail</strong></span></p>
9190 Failures of binding sockets.
9196 <p><span><strong class="command"><TYPE>ConnFail</strong></span></p>
9200 Failures of connecting sockets.
9206 <p><span><strong class="command"><TYPE>Conn</strong></span></p>
9210 Connections established successfully.
9216 <p><span><strong class="command"><TYPE>AcceptFail</strong></span></p>
9220 Failures of accepting incoming connection requests.
9221 This counter is not applicable to the
9222 <span><strong class="command">UDP</strong></span> and
9223 <span><strong class="command">FDwatch</strong></span> types.
9229 <p><span><strong class="command"><TYPE>Accept</strong></span></p>
9233 Incoming connections successfully accepted.
9234 This counter is not applicable to the
9235 <span><strong class="command">UDP</strong></span> and
9236 <span><strong class="command">FDwatch</strong></span> types.
9242 <p><span><strong class="command"><TYPE>SendErr</strong></span></p>
9246 Errors in socket send operations.
9247 This counter corresponds
9248 to <span><strong class="command">SErr</strong></span> counter of
9249 <span><strong class="command">BIND</strong></span> 8.
9255 <p><span><strong class="command"><TYPE>RecvErr</strong></span></p>
9259 Errors in socket receive operations.
9260 This includes errors of send operations on a
9261 connected UDP socket notified by an ICMP error
9269 <div class="sect3" lang="en">
9270 <div class="titlepage"><div><div><h4 class="title">
9271 <a name="id2598812"></a>Compatibility with <span class="emphasis"><em>BIND</em></span> 8 Counters</h4></div></div></div>
9273 Most statistics counters that were available
9274 in <span><strong class="command">BIND</strong></span> 8 are also supported in
9275 <span><strong class="command">BIND</strong></span> 9 as shown in the above tables.
9276 Here are notes about other counters that do not appear
9279 <div class="variablelist"><dl>
9280 <dt><span class="term"><span><strong class="command">RFwdR,SFwdR</strong></span></span></dt>
9282 These counters are not supported
9283 because <span><strong class="command">BIND</strong></span> 9 does not adopt
9284 the notion of <span class="emphasis"><em>forwarding</em></span>
9285 as <span><strong class="command">BIND</strong></span> 8 did.
9287 <dt><span class="term"><span><strong class="command">RAXFR</strong></span></span></dt>
9289 This counter is accessible in the Incoming Queries section.
9291 <dt><span class="term"><span><strong class="command">RIQ</strong></span></span></dt>
9293 This counter is accessible in the Incoming Requests section.
9295 <dt><span class="term"><span><strong class="command">ROpts</strong></span></span></dt>
9297 This counter is not supported
9298 because <span><strong class="command">BIND</strong></span> 9 does not care
9299 about IP options in the first place.
9306 <div class="navfooter">
9308 <table width="100%" summary="Navigation footer">
9310 <td width="40%" align="left">
9311 <a accesskey="p" href="Bv9ARM.ch05.html">Prev</a> </td>
9312 <td width="20%" align="center"> </td>
9313 <td width="40%" align="right"> <a accesskey="n" href="Bv9ARM.ch07.html">Next</a>
9317 <td width="40%" align="left" valign="top">Chapter 5. The <acronym class="acronym">BIND</acronym> 9 Lightweight Resolver </td>
9318 <td width="20%" align="center"><a accesskey="h" href="Bv9ARM.html">Home</a></td>
9319 <td width="40%" align="right" valign="top"> Chapter 7. <acronym class="acronym">BIND</acronym> 9 Security Considerations</td>