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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">-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>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="id2543468"></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="id2543493"></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">-f</span></dt>
84 Run the server in the foreground (i.e. do not daemonize).
86 <dt><span class="term">-g</span></dt>
88 Run the server in the foreground and force all logging
89 to <code class="filename">stderr</code>.
91 <dt><span class="term">-m <em class="replaceable"><code>flag</code></em></span></dt>
93 Turn on memory usage debugging flags. Possible flags are
94 <em class="replaceable"><code>usage</code></em>,
95 <em class="replaceable"><code>trace</code></em>,
96 <em class="replaceable"><code>record</code></em>,
97 <em class="replaceable"><code>size</code></em>, and
98 <em class="replaceable"><code>mctx</code></em>.
99 These correspond to the ISC_MEM_DEBUGXXXX flags described in
100 <code class="filename"><isc/mem.h></code>.
102 <dt><span class="term">-n <em class="replaceable"><code>#cpus</code></em></span></dt>
104 Create <em class="replaceable"><code>#cpus</code></em> worker threads
105 to take advantage of multiple CPUs. If not specified,
106 <span><strong class="command">named</strong></span> will try to determine the
107 number of CPUs present and create one thread per CPU.
108 If it is unable to determine the number of CPUs, a
109 single worker thread will be created.
111 <dt><span class="term">-p <em class="replaceable"><code>port</code></em></span></dt>
113 Listen for queries on port <em class="replaceable"><code>port</code></em>. If not
114 specified, the default is port 53.
116 <dt><span class="term">-s</span></dt>
119 Write memory usage statistics to <code class="filename">stdout</code> on exit.
121 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
122 <h3 class="title">Note</h3>
124 This option is mainly of interest to BIND 9 developers
125 and may be removed or changed in a future release.
129 <dt><span class="term">-S <em class="replaceable"><code>#max-socks</code></em></span></dt>
132 Allow <span><strong class="command">named</strong></span> to use up to
133 <em class="replaceable"><code>#max-socks</code></em> sockets.
135 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
136 <h3 class="title">Warning</h3>
138 This option should be unnecessary for the vast majority
140 The use of this option could even be harmful because the
141 specified value may exceed the limitation of the
142 underlying system API.
143 It is therefore set only when the default configuration
144 causes exhaustion of file descriptors and the
145 operational environment is known to support the
146 specified number of sockets.
147 Note also that the actual maximum number is normally a little
148 fewer than the specified value because
149 <span><strong class="command">named</strong></span> reserves some file descriptors
150 for its internal use.
154 <dt><span class="term">-t <em class="replaceable"><code>directory</code></em></span></dt>
157 to <em class="replaceable"><code>directory</code></em> after
158 processing the command line arguments, but before
159 reading the configuration file.
161 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
162 <h3 class="title">Warning</h3>
164 This option should be used in conjunction with the
165 <code class="option">-u</code> option, as chrooting a process
166 running as root doesn't enhance security on most
167 systems; the way <code class="function">chroot(2)</code> is
168 defined allows a process with root privileges to
169 escape a chroot jail.
173 <dt><span class="term">-u <em class="replaceable"><code>user</code></em></span></dt>
176 to <em class="replaceable"><code>user</code></em> after completing
177 privileged operations, such as creating sockets that
178 listen on privileged ports.
180 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
181 <h3 class="title">Note</h3>
183 On Linux, <span><strong class="command">named</strong></span> uses the kernel's
184 capability mechanism to drop all root privileges
185 except the ability to <code class="function">bind(2)</code> to
187 privileged port and set process resource limits.
188 Unfortunately, this means that the <code class="option">-u</code>
189 option only works when <span><strong class="command">named</strong></span> is
191 on kernel 2.2.18 or later, or kernel 2.3.99-pre3 or
192 later, since previous kernels did not allow privileges
193 to be retained after <code class="function">setuid(2)</code>.
197 <dt><span class="term">-v</span></dt>
199 Report the version number and exit.
201 <dt><span class="term">-V</span></dt>
203 Report the version number and build options, and exit.
205 <dt><span class="term">-x <em class="replaceable"><code>cache-file</code></em></span></dt>
208 Load data from <em class="replaceable"><code>cache-file</code></em> into the
209 cache of the default view.
211 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
212 <h3 class="title">Warning</h3>
214 This option must not be used. It is only of interest
215 to BIND 9 developers and may be removed or changed in a
222 <div class="refsect1" lang="en">
223 <a name="id2543928"></a><h2>SIGNALS</h2>
225 In routine operation, signals should not be used to control
226 the nameserver; <span><strong class="command">rndc</strong></span> should be used
229 <div class="variablelist"><dl>
230 <dt><span class="term">SIGHUP</span></dt>
232 Force a reload of the server.
234 <dt><span class="term">SIGINT, SIGTERM</span></dt>
236 Shut down the server.
240 The result of sending any other signals to the server is undefined.
243 <div class="refsect1" lang="en">
244 <a name="id2543976"></a><h2>CONFIGURATION</h2>
246 The <span><strong class="command">named</strong></span> configuration file is too complex
247 to describe in detail here. A complete description is provided
249 <em class="citetitle">BIND 9 Administrator Reference Manual</em>.
252 <div class="refsect1" lang="en">
253 <a name="id2543993"></a><h2>FILES</h2>
254 <div class="variablelist"><dl>
255 <dt><span class="term"><code class="filename">/etc/named.conf</code></span></dt>
257 The default configuration file.
259 <dt><span class="term"><code class="filename">/var/run/named/named.pid</code></span></dt>
261 The default process-id file.
265 <div class="refsect1" lang="en">
266 <a name="id2544033"></a><h2>SEE ALSO</h2>
267 <p><em class="citetitle">RFC 1033</em>,
268 <em class="citetitle">RFC 1034</em>,
269 <em class="citetitle">RFC 1035</em>,
270 <span class="citerefentry"><span class="refentrytitle">named-checkconf</span>(8)</span>,
271 <span class="citerefentry"><span class="refentrytitle">named-checkzone</span>(8)</span>,
272 <span class="citerefentry"><span class="refentrytitle">rndc</span>(8)</span>,
273 <span class="citerefentry"><span class="refentrytitle">lwresd</span>(8)</span>,
274 <span class="citerefentry"><span class="refentrytitle">named.conf</span>(5)</span>,
275 <em class="citetitle">BIND 9 Administrator Reference Manual</em>.
278 <div class="refsect1" lang="en">
279 <a name="id2544171"></a><h2>AUTHOR</h2>
280 <p><span class="corpauthor">Internet Systems Consortium</span>