1<!-- 2 - Copyright (C) 2004-2009, 2011, 2013, 2014 Internet Systems Consortium, Inc. ("ISC") 3 - Copyright (C) 2000, 2001, 2003 Internet Software Consortium. 4 - 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. 8 - 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. 16--> 17<!-- Id --> 18<html> 19<head> 20<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 21<title>named</title> 22<meta name="generator" content="DocBook XSL Stylesheets V1.71.1"> 23</head> 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"> 27<h2>Name</h2> 28<p><span class="application">named</span> — Internet domain name server</p> 29</div> 30<div class="refsynopsisdiv"> 31<h2>Synopsis</h2> 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">-D <em class="replaceable"><code>string</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> 33</div> 34<div class="refsect1" lang="en"> 35<a name="id2543515"></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. 40 </p> 41<p> 42 When invoked without arguments, <span><strong class="command">named</strong></span> 43 will 44 read the default configuration file 45 <code class="filename">/etc/named.conf</code>, read any initial 46 data, and listen for queries. 47 </p> 48</div> 49<div class="refsect1" lang="en"> 50<a name="id2543540"></a><h2>OPTIONS</h2> 51<div class="variablelist"><dl> 52<dt><span class="term">-4</span></dt> 53<dd><p> 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 56 exclusive. 57 </p></dd> 58<dt><span class="term">-6</span></dt> 59<dd><p> 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 62 exclusive. 63 </p></dd> 64<dt><span class="term">-c <em class="replaceable"><code>config-file</code></em></span></dt> 65<dd><p> 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 74 an absolute pathname. 75 </p></dd> 76<dt><span class="term">-d <em class="replaceable"><code>debug-level</code></em></span></dt> 77<dd><p> 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. 81 </p></dd> 82<dt><span class="term">-D <em class="replaceable"><code>string</code></em></span></dt> 83<dd><p> 84 Specifies a string that is used to identify a instance of 85 <span><strong class="command">named</strong></span> in a process listing. The contents 86 of <em class="replaceable"><code>string</code></em> are 87 not examined. 88 </p></dd> 89<dt><span class="term">-E <em class="replaceable"><code>engine-name</code></em></span></dt> 90<dd> 91<p> 92 When applicable, specifies the hardware to use for 93 cryptographic operations, such as a secure key store used 94 for signing. 95 </p> 96<p> 97 When BIND is built with OpenSSL PKCS#11 support, this defaults 98 to the string "pkcs11", which identifies an OpenSSL engine 99 that can drive a cryptographic accelerator or hardware service 100 module. When BIND is built with native PKCS#11 cryptography 101 (--enable-native-pkcs11), it defaults to the path of the PKCS#11 102 provider library specified via "--with-pkcs11". 103 </p> 104</dd> 105<dt><span class="term">-f</span></dt> 106<dd><p> 107 Run the server in the foreground (i.e. do not daemonize). 108 </p></dd> 109<dt><span class="term">-g</span></dt> 110<dd><p> 111 Run the server in the foreground and force all logging 112 to <code class="filename">stderr</code>. 113 </p></dd> 114<dt><span class="term">-m <em class="replaceable"><code>flag</code></em></span></dt> 115<dd><p> 116 Turn on memory usage debugging flags. Possible flags are 117 <em class="replaceable"><code>usage</code></em>, 118 <em class="replaceable"><code>trace</code></em>, 119 <em class="replaceable"><code>record</code></em>, 120 <em class="replaceable"><code>size</code></em>, and 121 <em class="replaceable"><code>mctx</code></em>. 122 These correspond to the ISC_MEM_DEBUGXXXX flags described in 123 <code class="filename"><isc/mem.h></code>. 124 </p></dd> 125<dt><span class="term">-n <em class="replaceable"><code>#cpus</code></em></span></dt> 126<dd><p> 127 Create <em class="replaceable"><code>#cpus</code></em> worker threads 128 to take advantage of multiple CPUs. If not specified, 129 <span><strong class="command">named</strong></span> will try to determine the 130 number of CPUs present and create one thread per CPU. 131 If it is unable to determine the number of CPUs, a 132 single worker thread will be created. 133 </p></dd> 134<dt><span class="term">-p <em class="replaceable"><code>port</code></em></span></dt> 135<dd><p> 136 Listen for queries on port <em class="replaceable"><code>port</code></em>. If not 137 specified, the default is port 53. 138 </p></dd> 139<dt><span class="term">-s</span></dt> 140<dd> 141<p> 142 Write memory usage statistics to <code class="filename">stdout</code> on exit. 143 </p> 144<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> 145<h3 class="title">Note</h3> 146<p> 147 This option is mainly of interest to BIND 9 developers 148 and may be removed or changed in a future release. 149 </p> 150</div> 151</dd> 152<dt><span class="term">-S <em class="replaceable"><code>#max-socks</code></em></span></dt> 153<dd> 154<p> 155 Allow <span><strong class="command">named</strong></span> to use up to 156 <em class="replaceable"><code>#max-socks</code></em> sockets. 157 The default value is 4096 on systems built with default 158 configuration options, and 21000 on systems built with 159 "configure --with-tuning=large". 160 </p> 161<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"> 162<h3 class="title">Warning</h3> 163<p> 164 This option should be unnecessary for the vast majority 165 of users. 166 The use of this option could even be harmful because the 167 specified value may exceed the limitation of the 168 underlying system API. 169 It is therefore set only when the default configuration 170 causes exhaustion of file descriptors and the 171 operational environment is known to support the 172 specified number of sockets. 173 Note also that the actual maximum number is normally a little 174 fewer than the specified value because 175 <span><strong class="command">named</strong></span> reserves some file descriptors 176 for its internal use. 177 </p> 178</div> 179</dd> 180<dt><span class="term">-t <em class="replaceable"><code>directory</code></em></span></dt> 181<dd> 182<p>Chroot 183 to <em class="replaceable"><code>directory</code></em> after 184 processing the command line arguments, but before 185 reading the configuration file. 186 </p> 187<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"> 188<h3 class="title">Warning</h3> 189<p> 190 This option should be used in conjunction with the 191 <code class="option">-u</code> option, as chrooting a process 192 running as root doesn't enhance security on most 193 systems; the way <code class="function">chroot(2)</code> is 194 defined allows a process with root privileges to 195 escape a chroot jail. 196 </p> 197</div> 198</dd> 199<dt><span class="term">-U <em class="replaceable"><code>#listeners</code></em></span></dt> 200<dd><p> 201 Use <em class="replaceable"><code>#listeners</code></em> 202 worker threads to listen for incoming UDP packets on each 203 address. If not specified, <span><strong class="command">named</strong></span> will 204 calculate a default value based on the number of detected 205 CPUs: 1 for 1 CPU, 2 for 2-4 CPUs, and the number of 206 detected CPUs divided by 2 for values higher than 4. 207 If <code class="option">-n</code> has been set to a higher value than 208 the number of detected CPUs, then <code class="option">-U</code> may 209 be increased as high as that value, but no higher. 210 </p></dd> 211<dt><span class="term">-u <em class="replaceable"><code>user</code></em></span></dt> 212<dd> 213<p>Setuid 214 to <em class="replaceable"><code>user</code></em> after completing 215 privileged operations, such as creating sockets that 216 listen on privileged ports. 217 </p> 218<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> 219<h3 class="title">Note</h3> 220<p> 221 On Linux, <span><strong class="command">named</strong></span> uses the kernel's 222 capability mechanism to drop all root privileges 223 except the ability to <code class="function">bind(2)</code> to 224 a 225 privileged port and set process resource limits. 226 Unfortunately, this means that the <code class="option">-u</code> 227 option only works when <span><strong class="command">named</strong></span> is 228 run 229 on kernel 2.2.18 or later, or kernel 2.3.99-pre3 or 230 later, since previous kernels did not allow privileges 231 to be retained after <code class="function">setuid(2)</code>. 232 </p> 233</div> 234</dd> 235<dt><span class="term">-v</span></dt> 236<dd><p> 237 Report the version number and exit. 238 </p></dd> 239<dt><span class="term">-V</span></dt> 240<dd><p> 241 Report the version number and build options, and exit. 242 </p></dd> 243<dt><span class="term">-x <em class="replaceable"><code>cache-file</code></em></span></dt> 244<dd> 245<p> 246 Load data from <em class="replaceable"><code>cache-file</code></em> into the 247 cache of the default view. 248 </p> 249<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"> 250<h3 class="title">Warning</h3> 251<p> 252 This option must not be used. It is only of interest 253 to BIND 9 developers and may be removed or changed in a 254 future release. 255 </p> 256</div> 257</dd> 258</dl></div> 259</div> 260<div class="refsect1" lang="en"> 261<a name="id2544123"></a><h2>SIGNALS</h2> 262<p> 263 In routine operation, signals should not be used to control 264 the nameserver; <span><strong class="command">rndc</strong></span> should be used 265 instead. 266 </p> 267<div class="variablelist"><dl> 268<dt><span class="term">SIGHUP</span></dt> 269<dd><p> 270 Force a reload of the server. 271 </p></dd> 272<dt><span class="term">SIGINT, SIGTERM</span></dt> 273<dd><p> 274 Shut down the server. 275 </p></dd> 276</dl></div> 277<p> 278 The result of sending any other signals to the server is undefined. 279 </p> 280</div> 281<div class="refsect1" lang="en"> 282<a name="id2544240"></a><h2>CONFIGURATION</h2> 283<p> 284 The <span><strong class="command">named</strong></span> configuration file is too complex 285 to describe in detail here. A complete description is provided 286 in the 287 <em class="citetitle">BIND 9 Administrator Reference Manual</em>. 288 </p> 289<p> 290 <span><strong class="command">named</strong></span> inherits the <code class="function">umask</code> 291 (file creation mode mask) from the parent process. If files 292 created by <span><strong class="command">named</strong></span>, such as journal files, 293 need to have custom permissions, the <code class="function">umask</code> 294 should be set explicitly in the script used to start the 295 <span><strong class="command">named</strong></span> process. 296 </p> 297</div> 298<div class="refsect1" lang="en"> 299<a name="id2544276"></a><h2>FILES</h2> 300<div class="variablelist"><dl> 301<dt><span class="term"><code class="filename">/etc/named.conf</code></span></dt> 302<dd><p> 303 The default configuration file. 304 </p></dd> 305<dt><span class="term"><code class="filename">/var/run/named/named.pid</code></span></dt> 306<dd><p> 307 The default process-id file. 308 </p></dd> 309</dl></div> 310</div> 311<div class="refsect1" lang="en"> 312<a name="id2544384"></a><h2>SEE ALSO</h2> 313<p><em class="citetitle">RFC 1033</em>, 314 <em class="citetitle">RFC 1034</em>, 315 <em class="citetitle">RFC 1035</em>, 316 <span class="citerefentry"><span class="refentrytitle">named-checkconf</span>(8)</span>, 317 <span class="citerefentry"><span class="refentrytitle">named-checkzone</span>(8)</span>, 318 <span class="citerefentry"><span class="refentrytitle">rndc</span>(8)</span>, 319 <span class="citerefentry"><span class="refentrytitle">lwresd</span>(8)</span>, 320 <span class="citerefentry"><span class="refentrytitle">named.conf</span>(5)</span>, 321 <em class="citetitle">BIND 9 Administrator Reference Manual</em>. 322 </p> 323</div> 324<div class="refsect1" lang="en"> 325<a name="id2544454"></a><h2>AUTHOR</h2> 326<p><span class="corpauthor">Internet Systems Consortium</span> 327 </p> 328</div> 329</div></body> 330</html> 331