2 - Copyright (C) 2004-2009, 2011, 2013-2015 Internet Systems Consortium, Inc. ("ISC")
3 - Copyright (C) 2000, 2001, 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.
19 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
21 <meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
23 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry">
24 <a name="man.named"></a><div class="titlepage"></div>
25 <div class="refnamediv">
27 <p><span class="application">named</span> — Internet domain name server</p>
29 <div class="refsynopsisdiv">
31 <div class="cmdsynopsis"><p><code class="command">named</code> [<code class="option">-4</code>] [<code class="option">-6</code>] [<code class="option">-c <em class="replaceable"><code>config-file</code></em></code>] [<code class="option">-d <em class="replaceable"><code>debug-level</code></em></code>] [<code class="option">-E <em class="replaceable"><code>engine-name</code></em></code>] [<code class="option">-f</code>] [<code class="option">-g</code>] [<code class="option">-M <em class="replaceable"><code>option</code></em></code>] [<code class="option">-m <em class="replaceable"><code>flag</code></em></code>] [<code class="option">-n <em class="replaceable"><code>#cpus</code></em></code>] [<code class="option">-p <em class="replaceable"><code>port</code></em></code>] [<code class="option">-s</code>] [<code class="option">-S <em class="replaceable"><code>#max-socks</code></em></code>] [<code class="option">-t <em class="replaceable"><code>directory</code></em></code>] [<code class="option">-U <em class="replaceable"><code>#listeners</code></em></code>] [<code class="option">-u <em class="replaceable"><code>user</code></em></code>] [<code class="option">-v</code>] [<code class="option">-V</code>] [<code class="option">-x <em class="replaceable"><code>cache-file</code></em></code>]</p></div>
33 <div class="refsection">
34 <a name="id-1.7"></a><h2>DESCRIPTION</h2>
35 <p><span class="command"><strong>named</strong></span>
36 is a Domain Name System (DNS) server,
37 part of the BIND 9 distribution from ISC. For more
38 information on the DNS, see RFCs 1033, 1034, and 1035.
41 When invoked without arguments, <span class="command"><strong>named</strong></span>
43 read the default configuration file
44 <code class="filename">/etc/named.conf</code>, read any initial
45 data, and listen for queries.
48 <div class="refsection">
49 <a name="id-1.8"></a><h2>OPTIONS</h2>
50 <div class="variablelist"><dl class="variablelist">
51 <dt><span class="term">-4</span></dt>
53 Use IPv4 only even if the host machine is capable of IPv6.
54 <code class="option">-4</code> and <code class="option">-6</code> are mutually
57 <dt><span class="term">-6</span></dt>
59 Use IPv6 only even if the host machine is capable of IPv4.
60 <code class="option">-4</code> and <code class="option">-6</code> are mutually
63 <dt><span class="term">-c <em class="replaceable"><code>config-file</code></em></span></dt>
65 Use <em class="replaceable"><code>config-file</code></em> as the
66 configuration file instead of the default,
67 <code class="filename">/etc/named.conf</code>. To
68 ensure that reloading the configuration file continues
69 to work after the server has changed its working
70 directory due to to a possible
71 <code class="option">directory</code> option in the configuration
72 file, <em class="replaceable"><code>config-file</code></em> should be
75 <dt><span class="term">-d <em class="replaceable"><code>debug-level</code></em></span></dt>
77 Set the daemon's debug level to <em class="replaceable"><code>debug-level</code></em>.
78 Debugging traces from <span class="command"><strong>named</strong></span> become
79 more verbose as the debug level increases.
81 <dt><span class="term">-E <em class="replaceable"><code>engine-name</code></em></span></dt>
83 Use a crypto hardware (OpenSSL engine) for the crypto operations
84 it supports, for instance re-signing with private keys from
85 a secure key store. When compiled with PKCS#11 support
86 <em class="replaceable"><code>engine-name</code></em>
87 defaults to pkcs11, the empty name resets it to no engine.
89 <dt><span class="term">-f</span></dt>
91 Run the server in the foreground (i.e. do not daemonize).
93 <dt><span class="term">-g</span></dt>
95 Run the server in the foreground and force all logging
96 to <code class="filename">stderr</code>.
98 <dt><span class="term">-M <em class="replaceable"><code>option</code></em></span></dt>
100 Sets the default memory context options. Currently
101 the only supported option is
102 <em class="replaceable"><code>external</code></em>,
103 which causes the internal memory manager to be bypassed
104 in favor of system-provided memory allocation functions.
106 <dt><span class="term">-m <em class="replaceable"><code>flag</code></em></span></dt>
108 Turn on memory usage debugging flags. Possible flags are
109 <em class="replaceable"><code>usage</code></em>,
110 <em class="replaceable"><code>trace</code></em>,
111 <em class="replaceable"><code>record</code></em>,
112 <em class="replaceable"><code>size</code></em>, and
113 <em class="replaceable"><code>mctx</code></em>.
114 These correspond to the ISC_MEM_DEBUGXXXX flags described in
115 <code class="filename"><isc/mem.h></code>.
117 <dt><span class="term">-n <em class="replaceable"><code>#cpus</code></em></span></dt>
119 Create <em class="replaceable"><code>#cpus</code></em> worker threads
120 to take advantage of multiple CPUs. If not specified,
121 <span class="command"><strong>named</strong></span> will try to determine the
122 number of CPUs present and create one thread per CPU.
123 If it is unable to determine the number of CPUs, a
124 single worker thread will be created.
126 <dt><span class="term">-p <em class="replaceable"><code>port</code></em></span></dt>
128 Listen for queries on port <em class="replaceable"><code>port</code></em>. If not
129 specified, the default is port 53.
131 <dt><span class="term">-s</span></dt>
134 Write memory usage statistics to <code class="filename">stdout</code> on exit.
136 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
137 <h3 class="title">Note</h3>
139 This option is mainly of interest to BIND 9 developers
140 and may be removed or changed in a future release.
144 <dt><span class="term">-S <em class="replaceable"><code>#max-socks</code></em></span></dt>
147 Allow <span class="command"><strong>named</strong></span> to use up to
148 <em class="replaceable"><code>#max-socks</code></em> sockets.
150 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
151 <h3 class="title">Warning</h3>
153 This option should be unnecessary for the vast majority
155 The use of this option could even be harmful because the
156 specified value may exceed the limitation of the
157 underlying system API.
158 It is therefore set only when the default configuration
159 causes exhaustion of file descriptors and the
160 operational environment is known to support the
161 specified number of sockets.
162 Note also that the actual maximum number is normally a little
163 fewer than the specified value because
164 <span class="command"><strong>named</strong></span> reserves some file descriptors
165 for its internal use.
169 <dt><span class="term">-t <em class="replaceable"><code>directory</code></em></span></dt>
172 to <em class="replaceable"><code>directory</code></em> after
173 processing the command line arguments, but before
174 reading the configuration file.
176 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
177 <h3 class="title">Warning</h3>
179 This option should be used in conjunction with the
180 <code class="option">-u</code> option, as chrooting a process
181 running as root doesn't enhance security on most
182 systems; the way <code class="function">chroot(2)</code> is
183 defined allows a process with root privileges to
184 escape a chroot jail.
188 <dt><span class="term">-U <em class="replaceable"><code>#listeners</code></em></span></dt>
190 Use <em class="replaceable"><code>#listeners</code></em>
191 worker threads to listen for incoming UDP packets on each
192 address. If not specified, <span class="command"><strong>named</strong></span> will
193 calculate a default value based on the number of detected
194 CPUs: 1 for 1 CPU, and the number of detected CPUs
195 minus one for machines with more than 1 CPU. This cannot
196 be increased to a value higher than the number of CPUs.
197 If <code class="option">-n</code> has been set to a higher value than
198 the number of detected CPUs, then <code class="option">-U</code> may
199 be increased as high as that value, but no higher.
200 On Windows, the number of UDP listeners is hardwired to 1
201 and this option has no effect.
203 <dt><span class="term">-u <em class="replaceable"><code>user</code></em></span></dt>
206 to <em class="replaceable"><code>user</code></em> after completing
207 privileged operations, such as creating sockets that
208 listen on privileged ports.
210 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
211 <h3 class="title">Note</h3>
213 On Linux, <span class="command"><strong>named</strong></span> uses the kernel's
214 capability mechanism to drop all root privileges
215 except the ability to <code class="function">bind(2)</code> to
217 privileged port and set process resource limits.
218 Unfortunately, this means that the <code class="option">-u</code>
219 option only works when <span class="command"><strong>named</strong></span> is
221 on kernel 2.2.18 or later, or kernel 2.3.99-pre3 or
222 later, since previous kernels did not allow privileges
223 to be retained after <code class="function">setuid(2)</code>.
227 <dt><span class="term">-v</span></dt>
229 Report the version number and exit.
231 <dt><span class="term">-V</span></dt>
233 Report the version number and build options, and exit.
235 <dt><span class="term">-x <em class="replaceable"><code>cache-file</code></em></span></dt>
238 Load data from <em class="replaceable"><code>cache-file</code></em> into the
239 cache of the default view.
241 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
242 <h3 class="title">Warning</h3>
244 This option must not be used. It is only of interest
245 to BIND 9 developers and may be removed or changed in a
252 <div class="refsection">
253 <a name="id-1.9"></a><h2>SIGNALS</h2>
255 In routine operation, signals should not be used to control
256 the nameserver; <span class="command"><strong>rndc</strong></span> should be used
259 <div class="variablelist"><dl class="variablelist">
260 <dt><span class="term">SIGHUP</span></dt>
262 Force a reload of the server.
264 <dt><span class="term">SIGINT, SIGTERM</span></dt>
266 Shut down the server.
270 The result of sending any other signals to the server is undefined.
273 <div class="refsection">
274 <a name="id-1.10"></a><h2>CONFIGURATION</h2>
276 The <span class="command"><strong>named</strong></span> configuration file is too complex
277 to describe in detail here. A complete description is provided
279 <em class="citetitle">BIND 9 Administrator Reference Manual</em>.
282 <span class="command"><strong>named</strong></span> inherits the <code class="function">umask</code>
283 (file creation mode mask) from the parent process. If files
284 created by <span class="command"><strong>named</strong></span>, such as journal files,
285 need to have custom permissions, the <code class="function">umask</code>
286 should be set explicitly in the script used to start the
287 <span class="command"><strong>named</strong></span> process.
290 <div class="refsection">
291 <a name="id-1.11"></a><h2>FILES</h2>
292 <div class="variablelist"><dl class="variablelist">
293 <dt><span class="term"><code class="filename">/etc/named.conf</code></span></dt>
295 The default configuration file.
297 <dt><span class="term"><code class="filename">/var/run/named/named.pid</code></span></dt>
299 The default process-id file.
303 <div class="refsection">
304 <a name="id-1.12"></a><h2>SEE ALSO</h2>
305 <p><em class="citetitle">RFC 1033</em>,
306 <em class="citetitle">RFC 1034</em>,
307 <em class="citetitle">RFC 1035</em>,
308 <span class="citerefentry"><span class="refentrytitle">named-checkconf</span>(8)</span>,
309 <span class="citerefentry"><span class="refentrytitle">named-checkzone</span>(8)</span>,
310 <span class="citerefentry"><span class="refentrytitle">rndc</span>(8)</span>,
311 <span class="citerefentry"><span class="refentrytitle">lwresd</span>(8)</span>,
312 <span class="citerefentry"><span class="refentrytitle">named.conf</span>(5)</span>,
313 <em class="citetitle">BIND 9 Administrator Reference Manual</em>.