man.host.html revision 335c82aebd0da12b401cfac28bd305da95a4d052
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - Copyright (C) 2004-2015 Internet Systems Consortium, Inc. ("ISC")
5347c0fcb04eaea19d9f39795646239f487c6207Tinderbox User - Copyright (C) 2000-2003 Internet Software Consortium.
5347c0fcb04eaea19d9f39795646239f487c6207Tinderbox User - Permission to use, copy, modify, and/or distribute this software for any
5347c0fcb04eaea19d9f39795646239f487c6207Tinderbox User - purpose with or without fee is hereby granted, provided that the above
5347c0fcb04eaea19d9f39795646239f487c6207Tinderbox User - copyright notice and this permission notice appear in all copies.
d6fa26d0adaec6c910115be34fe7a5a5f402c14fMark Andrews - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
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fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User - PERFORMANCE OF THIS SOFTWARE.
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7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User<a name="man.host"></a><div class="titlepage"></div>
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User<div class="cmdsynopsis"><p><code class="command">host</code> [<code class="option">-aCdlnrsTwv</code>] [<code class="option">-c <em class="replaceable"><code>class</code></em></code>] [<code class="option">-N <em class="replaceable"><code>ndots</code></em></code>] [<code class="option">-R <em class="replaceable"><code>number</code></em></code>] [<code class="option">-t <em class="replaceable"><code>type</code></em></code>] [<code class="option">-W <em class="replaceable"><code>wait</code></em></code>] [<code class="option">-m <em class="replaceable"><code>flag</code></em></code>] [<code class="option">-4</code>] [<code class="option">-6</code>] [<code class="option">-v</code>] [<code class="option">-V</code>] {name} [server]</p></div>
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User<p><span><strong class="command">host</strong></span>
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User is a simple utility for performing DNS lookups.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User It is normally used to convert names to IP addresses and vice versa.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User When no arguments or options are given,
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <span><strong class="command">host</strong></span>
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User prints a short summary of its command line arguments and options.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User<p><em class="parameter"><code>name</code></em> is the domain name that is to be
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User up. It can also be a dotted-decimal IPv4 address or a colon-delimited
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User IPv6 address, in which case <span><strong class="command">host</strong></span> will by
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User perform a reverse lookup for that address.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <em class="parameter"><code>server</code></em> is an optional argument which
fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User the name or IP address of the name server that <span><strong class="command">host</strong></span>
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User should query instead of the server or servers listed in
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <code class="filename">/etc/resolv.conf</code>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The <code class="option">-a</code> (all) option is equivalent to setting the
2eeb74d1cf5355dd98f6d507a10086e16bb08c4bTinderbox User <code class="option">-v</code> option and asking <span><strong class="command">host</strong></span> to make
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein a query of type ANY.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein When the <code class="option">-C</code> option is used, <span><strong class="command">host</strong></span>
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User will attempt to display the SOA records for zone
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <em class="parameter"><code>name</code></em> from all the listed
2eeb74d1cf5355dd98f6d507a10086e16bb08c4bTinderbox User authoritative name
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein servers for that zone. The list of name servers is defined by the NS
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein records that are found for the zone.
d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews The <code class="option">-c</code> option instructs to make a DNS query of class
2eeb74d1cf5355dd98f6d507a10086e16bb08c4bTinderbox User <em class="parameter"><code>class</code></em>. This can be used to lookup
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Chaosnet class resource records. The default class is IN (Internet).
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User Verbose output is generated by <span><strong class="command">host</strong></span> when
2eeb74d1cf5355dd98f6d507a10086e16bb08c4bTinderbox User <code class="option">-d</code> or <code class="option">-v</code> option is used. The two
03c0efc6892ef2ed17338b2ecbb2c5f23fbad0c9Tinderbox User options are equivalent. They have been provided for backwards
2eeb74d1cf5355dd98f6d507a10086e16bb08c4bTinderbox User compatibility. In previous versions, the <code class="option">-d</code> option
d8620c7234281056fdfd2ee40cf16636b8281092Tinderbox User switched on debugging traces and <code class="option">-v</code> enabled verbose
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein output. Verbose output can also be enabled by setting the
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <em class="parameter"><code>debug</code></em> option in
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <code class="filename">/etc/resolv.conf</code>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein List mode is selected by the <code class="option">-l</code> option. This makes
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <span><strong class="command">host</strong></span> perform a zone transfer for zone
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <em class="parameter"><code>name</code></em>. Transfer the zone printing out
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and address records (A/AAAA). If combined with <code class="option">-a</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein all records will be printed.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User option specifies that reverse lookups of IPv6 addresses should
b3cbb2f1ad021349e89807f3492df6e4e679cd56Mark Andrews use the IP6.INT domain as defined in RFC1886.
665a24faf6b3711e4012ac02ae5f0981c093ac1eTinderbox User The default is to use IP6.ARPA.
b3cbb2f1ad021349e89807f3492df6e4e679cd56Mark Andrews The <code class="option">-N</code> option sets the number of dots that have to be
b3cbb2f1ad021349e89807f3492df6e4e679cd56Mark Andrews in <em class="parameter"><code>name</code></em> for it to be considered
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User absolute. The
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User default value is that defined using the ndots statement in
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <code class="filename">/etc/resolv.conf</code>, or 1 if no ndots
fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User present. Names with fewer dots are interpreted as relative names and
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User will be searched for in the domains listed in the <span class="type">search</span>
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User or <span class="type">domain</span> directive in
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <code class="filename">/etc/resolv.conf</code>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The number of UDP retries for a lookup can be changed with the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="option">-R</code> option. <em class="parameter"><code>number</code></em>
61e1dc26d62c2a0059e3ca7efe2ad0f4a5b8df92Mark Andrews how many times <span><strong class="command">host</strong></span> will repeat a query
fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User not get answered. If
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="parameter"><code>number</code></em> is negative or zero, the
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User retries will default to 1. The default value is 1, or
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User the value of the <em class="parameter"><code>attempts</code></em> option in
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User <code class="filename">/etc/resolv.conf</code>, if set.
2eeb74d1cf5355dd98f6d507a10086e16bb08c4bTinderbox User Non-recursive queries can be made via the <code class="option">-r</code> option.
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User Setting this option clears the <span class="type">RD</span> — recursion
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User desired — bit in the query which <span><strong class="command">host</strong></span> makes.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User This should mean that the name server receiving the query will not
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User attempt to resolve <em class="parameter"><code>name</code></em>. The
2eeb74d1cf5355dd98f6d507a10086e16bb08c4bTinderbox User <code class="option">-r</code> option enables <span><strong class="command">host</strong></span>
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User the behavior of a name server by making non-recursive queries and
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User expecting to receive answers to those queries that are usually
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User referrals to other name servers.
2eeb74d1cf5355dd98f6d507a10086e16bb08c4bTinderbox User By default, <span><strong class="command">host</strong></span> uses UDP when making
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User <code class="option">-T</code> option makes it use a TCP connection when querying
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User the name server. TCP will be automatically selected for queries that
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User require it, such as zone transfer (AXFR) requests.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User The <code class="option">-4</code> option forces <span><strong class="command">host</strong></span> to only
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User use IPv4 query transport. The <code class="option">-6</code> option forces
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <span><strong class="command">host</strong></span> to only use IPv6 query transport.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User The <code class="option">-t</code> option is used to select the query type.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <em class="parameter"><code>type</code></em> can be any recognized query
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User NS, SOA, SIG, KEY, AXFR, etc. When no query type is specified,
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User <span><strong class="command">host</strong></span> automatically selects an appropriate
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User type. By default, it looks for A, AAAA, and MX records, but if the
2eeb74d1cf5355dd98f6d507a10086e16bb08c4bTinderbox User <code class="option">-C</code> option was given, queries will be made for SOA
6bcac4b58d16ee91184a72bd4ff05c41538fd932Tinderbox User records, and if <em class="parameter"><code>name</code></em> is a
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User dotted-decimal IPv4
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User address or colon-delimited IPv6 address, <span><strong class="command">host</strong></span> will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein query for PTR records. If a query type of IXFR is chosen the starting
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein serial number can be specified by appending an equal followed by the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein starting serial number (e.g. -t IXFR=12345678).
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User The time to wait for a reply can be controlled through the
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <code class="option">-W</code> and <code class="option">-w</code> options. The
fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User <code class="option">-W</code> option makes <span><strong class="command">host</strong></span>
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <em class="parameter"><code>wait</code></em> seconds. If <em class="parameter"><code>wait</code></em>
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User is less than one, the wait interval is set to one second. When the
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User <code class="option">-w</code> option is used, <span><strong class="command">host</strong></span>
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User effectively wait forever for a reply. The time to wait for a response
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User will be set to the number of seconds given by the hardware's maximum
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User value for an integer quantity. By default, <span><strong class="command">host</strong></span>
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User will wait for 5 seconds for UDP responses and 10 seconds for TCP
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User connections. These defaults can be overridden by the
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <em class="parameter"><code>timeout</code></em> option in
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <code class="filename">/etc/resolv.conf</code>.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User The <code class="option">-s</code> option tells <span><strong class="command">host</strong></span>
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User <span class="emphasis"><em>not</em></span> to send the query to the next nameserver
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User if any server responds with a SERVFAIL response, which is the
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User reverse of normal stub resolver behavior.
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User The <code class="option">-m</code> can be used to set the memory usage debugging
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <em class="parameter"><code>record</code></em>, <em class="parameter"><code>usage</code></em> and
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <em class="parameter"><code>trace</code></em>.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User The <code class="option">-V</code> option causes <span><strong class="command">host</strong></span>
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User to print the version number and exit.
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User If <span><strong class="command">host</strong></span> has been built with IDN (internationalized
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User domain name) support, it can accept and display non-ASCII domain names.
2eeb74d1cf5355dd98f6d507a10086e16bb08c4bTinderbox User <span><strong class="command">host</strong></span> appropriately converts character encoding of
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User domain name before sending a request to DNS server or displaying a
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User reply from the server.
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User If you'd like to turn off the IDN support for some reason, defines
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User the <code class="envar">IDN_DISABLE</code> environment variable.
2eeb74d1cf5355dd98f6d507a10086e16bb08c4bTinderbox User The IDN support is disabled if the variable is set when
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <span><strong class="command">host</strong></span> runs.
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User<p><code class="filename">/etc/resolv.conf</code>
0eea9763d88e3edf9b6de585f7cfbb08de977124Tinderbox User<p><span class="citerefentry"><span class="refentrytitle">dig</span>(1)</span>,
7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User <span class="citerefentry"><span class="refentrytitle">named</span>(8)</span>.
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7911e6f9de303bca5a3d8b34f4330c8f7cecffaeTinderbox User<p style="text-align: center;">BIND 9.11.0pre-alpha</p>