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24 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en">
25 <a name="man.named"></a><div class="titlepage"></div>
26 <div class="refnamediv">
28 <p><span class="application">named</span> — Internet domain name server</p>
30 <div class="refsynopsisdiv">
32 <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>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>
34 <div class="refsect1" lang="en">
35 <a name="id2543497"></a><h2>DESCRIPTION</h2>
36 <p><span><strong class="command">named</strong></span>
37 is a Domain Name System (DNS) server,
38 part of the BIND 9 distribution from ISC. For more
39 information on the DNS, see RFCs 1033, 1034, and 1035.
42 When invoked without arguments, <span><strong class="command">named</strong></span>
44 read the default configuration file
45 <code class="filename">/etc/named.conf</code>, read any initial
46 data, and listen for queries.
49 <div class="refsect1" lang="en">
50 <a name="id2543522"></a><h2>OPTIONS</h2>
51 <div class="variablelist"><dl>
52 <dt><span class="term">-4</span></dt>
54 Use IPv4 only even if the host machine is capable of IPv6.
55 <code class="option">-4</code> and <code class="option">-6</code> are mutually
58 <dt><span class="term">-6</span></dt>
60 Use IPv6 only even if the host machine is capable of IPv4.
61 <code class="option">-4</code> and <code class="option">-6</code> are mutually
64 <dt><span class="term">-c <em class="replaceable"><code>config-file</code></em></span></dt>
66 Use <em class="replaceable"><code>config-file</code></em> as the
67 configuration file instead of the default,
68 <code class="filename">/etc/named.conf</code>. To
69 ensure that reloading the configuration file continues
70 to work after the server has changed its working
71 directory due to to a possible
72 <code class="option">directory</code> option in the configuration
73 file, <em class="replaceable"><code>config-file</code></em> should be
76 <dt><span class="term">-d <em class="replaceable"><code>debug-level</code></em></span></dt>
78 Set the daemon's debug level to <em class="replaceable"><code>debug-level</code></em>.
79 Debugging traces from <span><strong class="command">named</strong></span> become
80 more verbose as the debug level increases.
82 <dt><span class="term">-E <em class="replaceable"><code>engine-name</code></em></span></dt>
84 Use a crypto hardware (OpenSSL engine) for the crypto operations
85 it supports, for instance re-signing with private keys from
86 a secure key store. When compiled with PKCS#11 support
87 <em class="replaceable"><code>engine-name</code></em>
88 defaults to pkcs11, the empty name resets it to no engine.
90 <dt><span class="term">-f</span></dt>
92 Run the server in the foreground (i.e. do not daemonize).
94 <dt><span class="term">-g</span></dt>
96 Run the server in the foreground and force all logging
97 to <code class="filename">stderr</code>.
99 <dt><span class="term">-m <em class="replaceable"><code>flag</code></em></span></dt>
101 Turn on memory usage debugging flags. Possible flags are
102 <em class="replaceable"><code>usage</code></em>,
103 <em class="replaceable"><code>trace</code></em>,
104 <em class="replaceable"><code>record</code></em>,
105 <em class="replaceable"><code>size</code></em>, and
106 <em class="replaceable"><code>mctx</code></em>.
107 These correspond to the ISC_MEM_DEBUGXXXX flags described in
108 <code class="filename"><isc/mem.h></code>.
110 <dt><span class="term">-n <em class="replaceable"><code>#cpus</code></em></span></dt>
112 Create <em class="replaceable"><code>#cpus</code></em> worker threads
113 to take advantage of multiple CPUs. If not specified,
114 <span><strong class="command">named</strong></span> will try to determine the
115 number of CPUs present and create one thread per CPU.
116 If it is unable to determine the number of CPUs, a
117 single worker thread will be created.
119 <dt><span class="term">-p <em class="replaceable"><code>port</code></em></span></dt>
121 Listen for queries on port <em class="replaceable"><code>port</code></em>. If not
122 specified, the default is port 53.
124 <dt><span class="term">-s</span></dt>
127 Write memory usage statistics to <code class="filename">stdout</code> on exit.
129 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
130 <h3 class="title">Note</h3>
132 This option is mainly of interest to BIND 9 developers
133 and may be removed or changed in a future release.
137 <dt><span class="term">-S <em class="replaceable"><code>#max-socks</code></em></span></dt>
140 Allow <span><strong class="command">named</strong></span> to use up to
141 <em class="replaceable"><code>#max-socks</code></em> sockets.
143 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
144 <h3 class="title">Warning</h3>
146 This option should be unnecessary for the vast majority
148 The use of this option could even be harmful because the
149 specified value may exceed the limitation of the
150 underlying system API.
151 It is therefore set only when the default configuration
152 causes exhaustion of file descriptors and the
153 operational environment is known to support the
154 specified number of sockets.
155 Note also that the actual maximum number is normally a little
156 fewer than the specified value because
157 <span><strong class="command">named</strong></span> reserves some file descriptors
158 for its internal use.
162 <dt><span class="term">-t <em class="replaceable"><code>directory</code></em></span></dt>
165 to <em class="replaceable"><code>directory</code></em> after
166 processing the command line arguments, but before
167 reading the configuration file.
169 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
170 <h3 class="title">Warning</h3>
172 This option should be used in conjunction with the
173 <code class="option">-u</code> option, as chrooting a process
174 running as root doesn't enhance security on most
175 systems; the way <code class="function">chroot(2)</code> is
176 defined allows a process with root privileges to
177 escape a chroot jail.
181 <dt><span class="term">-U <em class="replaceable"><code>#listeners</code></em></span></dt>
183 Use <em class="replaceable"><code>#listeners</code></em>
184 worker threads to listen for incoming UDP packets on each
185 address. If not specified, <span><strong class="command">named</strong></span> will
186 use the number of detected CPUs. If <code class="option">-n</code>
187 has been set to a higher value than the number of CPUs,
188 then <code class="option">-U</code> may be increased as high as that
189 value, but no higher.
191 <dt><span class="term">-u <em class="replaceable"><code>user</code></em></span></dt>
194 to <em class="replaceable"><code>user</code></em> after completing
195 privileged operations, such as creating sockets that
196 listen on privileged ports.
198 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
199 <h3 class="title">Note</h3>
201 On Linux, <span><strong class="command">named</strong></span> uses the kernel's
202 capability mechanism to drop all root privileges
203 except the ability to <code class="function">bind(2)</code> to
205 privileged port and set process resource limits.
206 Unfortunately, this means that the <code class="option">-u</code>
207 option only works when <span><strong class="command">named</strong></span> is
209 on kernel 2.2.18 or later, or kernel 2.3.99-pre3 or
210 later, since previous kernels did not allow privileges
211 to be retained after <code class="function">setuid(2)</code>.
215 <dt><span class="term">-v</span></dt>
217 Report the version number and exit.
219 <dt><span class="term">-V</span></dt>
221 Report the version number and build options, and exit.
223 <dt><span class="term">-x <em class="replaceable"><code>cache-file</code></em></span></dt>
226 Load data from <em class="replaceable"><code>cache-file</code></em> into the
227 cache of the default view.
229 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
230 <h3 class="title">Warning</h3>
232 This option must not be used. It is only of interest
233 to BIND 9 developers and may be removed or changed in a
240 <div class="refsect1" lang="en">
241 <a name="id2544012"></a><h2>SIGNALS</h2>
243 In routine operation, signals should not be used to control
244 the nameserver; <span><strong class="command">rndc</strong></span> should be used
247 <div class="variablelist"><dl>
248 <dt><span class="term">SIGHUP</span></dt>
250 Force a reload of the server.
252 <dt><span class="term">SIGINT, SIGTERM</span></dt>
254 Shut down the server.
258 The result of sending any other signals to the server is undefined.
261 <div class="refsect1" lang="en">
262 <a name="id2544060"></a><h2>CONFIGURATION</h2>
264 The <span><strong class="command">named</strong></span> configuration file is too complex
265 to describe in detail here. A complete description is provided
267 <em class="citetitle">BIND 9 Administrator Reference Manual</em>.
270 <span><strong class="command">named</strong></span> inherits the <code class="function">umask</code>
271 (file creation mode mask) from the parent process. If files
272 created by <span><strong class="command">named</strong></span>, such as journal files,
273 need to have custom permissions, the <code class="function">umask</code>
274 should be set explicitly in the script used to start the
275 <span><strong class="command">named</strong></span> process.
278 <div class="refsect1" lang="en">
279 <a name="id2544233"></a><h2>FILES</h2>
280 <div class="variablelist"><dl>
281 <dt><span class="term"><code class="filename">/etc/named.conf</code></span></dt>
283 The default configuration file.
285 <dt><span class="term"><code class="filename">/var/run/named/named.pid</code></span></dt>
287 The default process-id file.
291 <div class="refsect1" lang="en">
292 <a name="id2544273"></a><h2>SEE ALSO</h2>
293 <p><em class="citetitle">RFC 1033</em>,
294 <em class="citetitle">RFC 1034</em>,
295 <em class="citetitle">RFC 1035</em>,
296 <span class="citerefentry"><span class="refentrytitle">named-checkconf</span>(8)</span>,
297 <span class="citerefentry"><span class="refentrytitle">named-checkzone</span>(8)</span>,
298 <span class="citerefentry"><span class="refentrytitle">rndc</span>(8)</span>,
299 <span class="citerefentry"><span class="refentrytitle">lwresd</span>(8)</span>,
300 <span class="citerefentry"><span class="refentrytitle">named.conf</span>(5)</span>,
301 <em class="citetitle">BIND 9 Administrator Reference Manual</em>.
304 <div class="refsect1" lang="en">
305 <a name="id2544343"></a><h2>AUTHOR</h2>
306 <p><span class="corpauthor">Internet Systems Consortium</span>