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: man.nsupdate.html,v 1.22.14.21.2.1 2010/02/25 12:16:49 tbox Exp $ -->
20 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
21 <title>nsupdate</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.ch10.html" title="Manual pages">
25 <link rel="prev" href="man.named.html" title="named">
26 <link rel="next" href="man.rndc.html" title="rndc">
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"><span class="application">nsupdate</span></th></tr>
33 <td width="20%" align="left">
34 <a accesskey="p" href="man.named.html">Prev</a> </td>
35 <th width="60%" align="center">Manual pages</th>
36 <td width="20%" align="right"> <a accesskey="n" href="man.rndc.html">Next</a>
42 <div class="refentry" lang="en">
43 <a name="man.nsupdate"></a><div class="titlepage"></div>
44 <div class="refnamediv">
46 <p><span class="application">nsupdate</span> — Dynamic DNS update utility</p>
48 <div class="refsynopsisdiv">
50 <div class="cmdsynopsis"><p><code class="command">nsupdate</code> [<code class="option">-d</code>] [<code class="option">-D</code>] [[<code class="option">-g</code>] | [<code class="option">-o</code>] | [<code class="option">-y <em class="replaceable"><code>[<span class="optional">hmac:</span>]keyname:secret</code></em></code>] | [<code class="option">-k <em class="replaceable"><code>keyfile</code></em></code>]] [<code class="option">-t <em class="replaceable"><code>timeout</code></em></code>] [<code class="option">-u <em class="replaceable"><code>udptimeout</code></em></code>] [<code class="option">-r <em class="replaceable"><code>udpretries</code></em></code>] [<code class="option">-R <em class="replaceable"><code>randomdev</code></em></code>] [<code class="option">-v</code>] [filename]</p></div>
52 <div class="refsect1" lang="en">
53 <a name="id2611204"></a><h2>DESCRIPTION</h2>
54 <p><span><strong class="command">nsupdate</strong></span>
55 is used to submit Dynamic DNS Update requests as defined in RFC2136
57 This allows resource records to be added or removed from a zone
58 without manually editing the zone file.
59 A single update request can contain requests to add or remove more than
64 Zones that are under dynamic control via
65 <span><strong class="command">nsupdate</strong></span>
66 or a DHCP server should not be edited by hand.
68 conflict with dynamic updates and cause data to be lost.
71 The resource records that are dynamically added or removed with
72 <span><strong class="command">nsupdate</strong></span>
73 have to be in the same zone.
74 Requests are sent to the zone's master server.
75 This is identified by the MNAME field of the zone's SOA record.
79 <code class="option">-d</code>
81 <span><strong class="command">nsupdate</strong></span>
82 operate in debug mode.
83 This provides tracing information about the update requests that are
84 made and the replies received from the name server.
87 The <code class="option">-D</code> option makes <span><strong class="command">nsupdate</strong></span>
88 report additional debugging information to <code class="option">-d</code>.
91 Transaction signatures can be used to authenticate the Dynamic
92 DNS updates. These use the TSIG resource record type described
93 in RFC2845 or the SIG(0) record described in RFC3535 and
94 RFC2931 or GSS-TSIG as described in RFC3645. TSIG relies on
95 a shared secret that should only be known to
96 <span><strong class="command">nsupdate</strong></span> and the name server. Currently,
97 the only supported encryption algorithm for TSIG is HMAC-MD5,
98 which is defined in RFC 2104. Once other algorithms are
99 defined for TSIG, applications will need to ensure they select
100 the appropriate algorithm as well as the key when authenticating
101 each other. For instance, suitable <span class="type">key</span> and
102 <span class="type">server</span> statements would be added to
103 <code class="filename">/etc/named.conf</code> so that the name server
104 can associate the appropriate secret key and algorithm with
105 the IP address of the client application that will be using
106 TSIG authentication. SIG(0) uses public key cryptography.
107 To use a SIG(0) key, the public key must be stored in a KEY
108 record in a zone served by the name server.
109 <span><strong class="command">nsupdate</strong></span> does not read
110 <code class="filename">/etc/named.conf</code>.
111 GSS-TSIG uses Kerberos credentials.
113 <p><span><strong class="command">nsupdate</strong></span>
114 uses the <code class="option">-y</code> or <code class="option">-k</code> option
115 to provide the shared secret needed to generate a TSIG record
116 for authenticating Dynamic DNS update requests, default type
117 HMAC-MD5. These options are mutually exclusive. With the
118 <code class="option">-k</code> option, <span><strong class="command">nsupdate</strong></span> reads
119 the shared secret from the file <em class="parameter"><code>keyfile</code></em>,
120 whose name is of the form
121 <code class="filename">K{name}.+157.+{random}.private</code>. For
122 historical reasons, the file
123 <code class="filename">K{name}.+157.+{random}.key</code> must also be
124 present. When the <code class="option">-y</code> option is used, a
125 signature is generated from
126 [<span class="optional"><em class="parameter"><code>hmac:</code></em></span>]<em class="parameter"><code>keyname:secret.</code></em>
127 <em class="parameter"><code>keyname</code></em> is the name of the key, and
128 <em class="parameter"><code>secret</code></em> is the base64 encoded shared
129 secret. Use of the <code class="option">-y</code> option is discouraged
130 because the shared secret is supplied as a command line
131 argument in clear text. This may be visible in the output
133 <span class="citerefentry"><span class="refentrytitle">ps</span>(1)</span> or in a history file maintained by the user's
137 The <code class="option">-k</code> may also be used to specify a SIG(0) key used
138 to authenticate Dynamic DNS update requests. In this case, the key
139 specified is not an HMAC-MD5 key.
142 The <code class="option">-g</code> and <code class="option">-o</code> specify that
143 GSS-TSIG is to be used. The <code class="option">-o</code> should only
144 be used with old Microsoft Windows 2000 servers.
148 <span><strong class="command">nsupdate</strong></span>
149 uses UDP to send update requests to the name server unless they are too
150 large to fit in a UDP request in which case TCP will be used.
152 <code class="option">-v</code>
154 <span><strong class="command">nsupdate</strong></span>
155 use a TCP connection.
156 This may be preferable when a batch of update requests is made.
159 The <code class="option">-t</code> option sets the maximum time an update request
161 take before it is aborted. The default is 300 seconds. Zero can be
163 to disable the timeout.
166 The <code class="option">-u</code> option sets the UDP retry interval. The default
168 3 seconds. If zero, the interval will be computed from the timeout
170 and number of UDP retries.
173 The <code class="option">-r</code> option sets the number of UDP retries. The
175 3. If zero, only one update request will be made.
178 The <code class="option">-R <em class="replaceable"><code>randomdev</code></em></code> option
179 specifies a source of randomness. If the operating system
180 does not provide a <code class="filename">/dev/random</code> or
181 equivalent device, the default source of randomness is keyboard
182 input. <code class="filename">randomdev</code> specifies the name of
183 a character device or file containing random data to be used
184 instead of the default. The special value
185 <code class="filename">keyboard</code> indicates that keyboard input
186 should be used. This option may be specified multiple times.
189 <div class="refsect1" lang="en">
190 <a name="id2611667"></a><h2>INPUT FORMAT</h2>
191 <p><span><strong class="command">nsupdate</strong></span>
193 <em class="parameter"><code>filename</code></em>
195 Each command is supplied on exactly one line of input.
196 Some commands are for administrative purposes.
197 The others are either update instructions or prerequisite checks on the
198 contents of the zone.
199 These checks set conditions that some name or set of
200 resource records (RRset) either exists or is absent from the zone.
201 These conditions must be met if the entire update request is to succeed.
202 Updates will be rejected if the tests for the prerequisite conditions
206 Every update request consists of zero or more prerequisites
207 and zero or more updates.
208 This allows a suitably authenticated update request to proceed if some
209 specified resource records are present or missing from the zone.
210 A blank input line (or the <span><strong class="command">send</strong></span> command)
212 accumulated commands to be sent as one Dynamic DNS update request to the
216 The command formats and their meaning are as follows:
218 <div class="variablelist"><dl>
219 <dt><span class="term">
220 <span><strong class="command">server</strong></span>
225 Sends all dynamic update requests to the name server
226 <em class="parameter"><code>servername</code></em>.
227 When no server statement is provided,
228 <span><strong class="command">nsupdate</strong></span>
229 will send updates to the master server of the correct zone.
230 The MNAME field of that zone's SOA record will identify the
232 server for that zone.
233 <em class="parameter"><code>port</code></em>
234 is the port number on
235 <em class="parameter"><code>servername</code></em>
236 where the dynamic update requests get sent.
237 If no port number is specified, the default DNS port number of
241 <dt><span class="term">
242 <span><strong class="command">local</strong></span>
247 Sends all dynamic update requests using the local
248 <em class="parameter"><code>address</code></em>.
250 When no local statement is provided,
251 <span><strong class="command">nsupdate</strong></span>
252 will send updates using an address and port chosen by the
254 <em class="parameter"><code>port</code></em>
255 can additionally be used to make requests come from a specific
257 If no port number is specified, the system will assign one.
259 <dt><span class="term">
260 <span><strong class="command">zone</strong></span>
264 Specifies that all updates are to be made to the zone
265 <em class="parameter"><code>zonename</code></em>.
267 <em class="parameter"><code>zone</code></em>
268 statement is provided,
269 <span><strong class="command">nsupdate</strong></span>
270 will attempt determine the correct zone to update based on the
273 <dt><span class="term">
274 <span><strong class="command">class</strong></span>
278 Specify the default class.
279 If no <em class="parameter"><code>class</code></em> is specified, the
281 <em class="parameter"><code>IN</code></em>.
283 <dt><span class="term">
284 <span><strong class="command">ttl</strong></span>
288 Specify the default time to live for records to be added.
289 The value <em class="parameter"><code>none</code></em> will clear the default
292 <dt><span class="term">
293 <span><strong class="command">key</strong></span>
298 Specifies that all updates are to be TSIG-signed using the
299 <em class="parameter"><code>keyname</code></em> <em class="parameter"><code>keysecret</code></em> pair.
300 The <span><strong class="command">key</strong></span> command
301 overrides any key specified on the command line via
302 <code class="option">-y</code> or <code class="option">-k</code>.
304 <dt><span class="term">
305 <span><strong class="command">prereq nxdomain</strong></span>
309 Requires that no resource record of any type exists with name
310 <em class="parameter"><code>domain-name</code></em>.
312 <dt><span class="term">
313 <span><strong class="command">prereq yxdomain</strong></span>
318 <em class="parameter"><code>domain-name</code></em>
319 exists (has as at least one resource record, of any type).
321 <dt><span class="term">
322 <span><strong class="command">prereq nxrrset</strong></span>
328 Requires that no resource record exists of the specified
329 <em class="parameter"><code>type</code></em>,
330 <em class="parameter"><code>class</code></em>
332 <em class="parameter"><code>domain-name</code></em>.
334 <em class="parameter"><code>class</code></em>
335 is omitted, IN (internet) is assumed.
337 <dt><span class="term">
338 <span><strong class="command">prereq yxrrset</strong></span>
344 This requires that a resource record of the specified
345 <em class="parameter"><code>type</code></em>,
346 <em class="parameter"><code>class</code></em>
348 <em class="parameter"><code>domain-name</code></em>
351 <em class="parameter"><code>class</code></em>
352 is omitted, IN (internet) is assumed.
354 <dt><span class="term">
355 <span><strong class="command">prereq yxrrset</strong></span>
363 <em class="parameter"><code>data</code></em>
364 from each set of prerequisites of this form
366 <em class="parameter"><code>type</code></em>,
367 <em class="parameter"><code>class</code></em>,
369 <em class="parameter"><code>domain-name</code></em>
370 are combined to form a set of RRs. This set of RRs must
371 exactly match the set of RRs existing in the zone at the
373 <em class="parameter"><code>type</code></em>,
374 <em class="parameter"><code>class</code></em>,
376 <em class="parameter"><code>domain-name</code></em>.
378 <em class="parameter"><code>data</code></em>
379 are written in the standard text representation of the resource
383 <dt><span class="term">
384 <span><strong class="command">update delete</strong></span>
391 Deletes any resource records named
392 <em class="parameter"><code>domain-name</code></em>.
394 <em class="parameter"><code>type</code></em>
396 <em class="parameter"><code>data</code></em>
397 is provided, only matching resource records will be removed.
398 The internet class is assumed if
399 <em class="parameter"><code>class</code></em>
401 <em class="parameter"><code>ttl</code></em>
402 is ignored, and is only allowed for compatibility.
404 <dt><span class="term">
405 <span><strong class="command">update add</strong></span>
413 Adds a new resource record with the specified
414 <em class="parameter"><code>ttl</code></em>,
415 <em class="parameter"><code>class</code></em>
417 <em class="parameter"><code>data</code></em>.
419 <dt><span class="term">
420 <span><strong class="command">show</strong></span>
423 Displays the current message, containing all of the
425 updates specified since the last send.
427 <dt><span class="term">
428 <span><strong class="command">send</strong></span>
431 Sends the current message. This is equivalent to entering a
434 <dt><span class="term">
435 <span><strong class="command">answer</strong></span>
440 <dt><span class="term">
441 <span><strong class="command">debug</strong></span>
450 Lines beginning with a semicolon are comments and are ignored.
453 <div class="refsect1" lang="en">
454 <a name="id2660691"></a><h2>EXAMPLES</h2>
456 The examples below show how
457 <span><strong class="command">nsupdate</strong></span>
458 could be used to insert and delete resource records from the
459 <span class="type">example.com</span>
461 Notice that the input in each example contains a trailing blank line so
463 a group of commands are sent as one dynamic update request to the
464 master name server for
465 <span class="type">example.com</span>.
468 <pre class="programlisting">
470 > update delete oldhost.example.com A
471 > update add newhost.example.com 86400 A 172.16.1.1
478 <span class="type">oldhost.example.com</span>
481 <span class="type">newhost.example.com</span>
482 with IP address 172.16.1.1 is added.
483 The newly-added record has a 1 day TTL (86400 seconds).
485 <pre class="programlisting">
487 > prereq nxdomain nickname.example.com
488 > update add nickname.example.com 86400 CNAME somehost.example.com
494 The prerequisite condition gets the name server to check that there
495 are no resource records of any type for
496 <span class="type">nickname.example.com</span>.
498 If there are, the update request fails.
499 If this name does not exist, a CNAME for it is added.
500 This ensures that when the CNAME is added, it cannot conflict with the
501 long-standing rule in RFC1034 that a name must not exist as any other
502 record type if it exists as a CNAME.
503 (The rule has been updated for DNSSEC in RFC2535 to allow CNAMEs to have
504 RRSIG, DNSKEY and NSEC records.)
507 <div class="refsect1" lang="en">
508 <a name="id2660741"></a><h2>FILES</h2>
509 <div class="variablelist"><dl>
510 <dt><span class="term"><code class="constant">/etc/resolv.conf</code></span></dt>
512 used to identify default name server
514 <dt><span class="term"><code class="constant">K{name}.+157.+{random}.key</code></span></dt>
516 base-64 encoding of HMAC-MD5 key created by
517 <span class="citerefentry"><span class="refentrytitle">dnssec-keygen</span>(8)</span>.
519 <dt><span class="term"><code class="constant">K{name}.+157.+{random}.private</code></span></dt>
521 base-64 encoding of HMAC-MD5 key created by
522 <span class="citerefentry"><span class="refentrytitle">dnssec-keygen</span>(8)</span>.
526 <div class="refsect1" lang="en">
527 <a name="id2660810"></a><h2>SEE ALSO</h2>
528 <p><span class="citerefentry"><span class="refentrytitle">RFC2136</span></span>,
529 <span class="citerefentry"><span class="refentrytitle">RFC3007</span></span>,
530 <span class="citerefentry"><span class="refentrytitle">RFC2104</span></span>,
531 <span class="citerefentry"><span class="refentrytitle">RFC2845</span></span>,
532 <span class="citerefentry"><span class="refentrytitle">RFC1034</span></span>,
533 <span class="citerefentry"><span class="refentrytitle">RFC2535</span></span>,
534 <span class="citerefentry"><span class="refentrytitle">RFC2931</span></span>,
535 <span class="citerefentry"><span class="refentrytitle">named</span>(8)</span>,
536 <span class="citerefentry"><span class="refentrytitle">dnssec-keygen</span>(8)</span>.
539 <div class="refsect1" lang="en">
540 <a name="id2660881"></a><h2>BUGS</h2>
542 The TSIG key is redundantly stored in two separate files.
543 This is a consequence of nsupdate using the DST library
544 for its cryptographic operations, and may change in future
549 <div class="navfooter">
551 <table width="100%" summary="Navigation footer">
553 <td width="40%" align="left">
554 <a accesskey="p" href="man.named.html">Prev</a> </td>
555 <td width="20%" align="center"><a accesskey="u" href="Bv9ARM.ch10.html">Up</a></td>
556 <td width="40%" align="right"> <a accesskey="n" href="man.rndc.html">Next</a>
560 <td width="40%" align="left" valign="top">
561 <span class="application">named</span> </td>
562 <td width="20%" align="center"><a accesskey="h" href="Bv9ARM.html">Home</a></td>
563 <td width="40%" align="right" valign="top"> <span class="application">rndc</span>