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11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User - Copyright (C) 2004-2007 Internet Systems Consortium, Inc. ("ISC")
75c0816e8295e180f4bc7f10db3d0d880383bc1cMark Andrews - Copyright (C) 2000-2003 Internet Software Consortium.
4a14ce5ba00ab7bc55c99ffdcf59c7a4ab902721Automatic Updater - Permission to use, copy, modify, and distribute this software for any
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - purpose with or without fee is hereby granted, provided that the above
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - copyright notice and this permission notice appear in all copies.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - 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
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - PERFORMANCE OF THIS SOFTWARE.
ea94d370123a5892f6c47a97f21d1b28d44bb168Tinderbox User<!-- $Id: man.host.html,v 1.44 2007/05/08 02:30:42 marka Exp $ -->
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60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<link rel="start" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual">
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5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<a name="man.host"></a><div class="titlepage"></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<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>] {name} [server]</p></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><span><strong class="command">host</strong></span>
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User is a simple utility for performing DNS lookups.
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User It is normally used to convert names to IP addresses and vice versa.
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User When no arguments or options are given,
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User <span><strong class="command">host</strong></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein prints a short summary of its command line arguments and options.
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User<p><em class="parameter"><code>name</code></em> is the domain name that is to be
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User up. It can also be a dotted-decimal IPv4 address or a colon-delimited
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User IPv6 address, in which case <span><strong class="command">host</strong></span> will by
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein perform a reverse lookup for that address.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="parameter"><code>server</code></em> is an optional argument which
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the name or IP address of the name server that <span><strong class="command">host</strong></span>
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User should query instead of the server or servers listed in
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User <code class="filename">/etc/resolv.conf</code>.
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User The <code class="option">-a</code> (all) option is equivalent to setting the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <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>
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User will attempt to display the SOA records for zone
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User <em class="parameter"><code>name</code></em> from all the listed
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein authoritative name
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User servers for that zone. The list of name servers is defined by the NS
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User records that are found for the zone.
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User The <code class="option">-c</code> option instructs to make a DNS query of class
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <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).
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Verbose output is generated by <span><strong class="command">host</strong></span> when
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="option">-d</code> or <code class="option">-v</code> option is used. The two
5d564da348e890e42f63eebf2dced9a05b41f4fbTinderbox User options are equivalent. They have been provided for backwards
5d564da348e890e42f63eebf2dced9a05b41f4fbTinderbox User compatibility. In previous versions, the <code class="option">-d</code> option
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein switched on debugging traces and <code class="option">-v</code> enabled verbose
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User List mode is selected by the <code class="option">-l</code> option. This makes
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User <span><strong class="command">host</strong></span> perform a zone transfer for zone
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox 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>
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User all records will be printed.
5d564da348e890e42f63eebf2dced9a05b41f4fbTinderbox User option specifies that reverse lookups of IPv6 addresses should
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User use the IP6.INT domain as defined in RFC1886.
11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User The default is to use IP6.ARPA.
6f64d4ab8e68f9b2333bcbfc755396d29a4a9d7cAutomatic Updater The <code class="option">-N</code> option sets the number of dots that have to be
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User in <em class="parameter"><code>name</code></em> for it to be considered
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User absolute. The
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User default value is that defined using the ndots statement in
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User <code class="filename">/etc/resolv.conf</code>, or 1 if no ndots
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User present. Names with fewer dots are interpreted as relative names and
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User will be searched for in the domains listed in the <span class="type">search</span>
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User or <span class="type">domain</span> directive in
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User <code class="filename">/etc/resolv.conf</code>.
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User The number of UDP retries for a lookup can be changed with the
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User <code class="option">-R</code> option. <em class="parameter"><code>number</code></em>
44d0f0256fbdce130a18655023c3b06bacacbd61Automatic Updater how many times <span><strong class="command">host</strong></span> will repeat a query
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User not get answered. The default number of retries is 1. If
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User <em class="parameter"><code>number</code></em> is negative or zero, the
bbbf2e27d3a981163dab139497d6b2dc85449db0Tinderbox User retries will default to 1.
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User Non-recursive queries can be made via the <code class="option">-r</code> option.
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User Setting this option clears the <span class="type">RD</span> — recursion
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User desired — bit in the query which <span><strong class="command">host</strong></span> makes.
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User This should mean that the name server receiving the query will not
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User attempt to resolve <em class="parameter"><code>name</code></em>. The
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User <code class="option">-r</code> option enables <span><strong class="command">host</strong></span>
bcf15a19ae0efa72a22cdfb50666a3c6ce39eb9fTinderbox User the behaviour of a name server by making non-recursive queries and
44d0f0256fbdce130a18655023c3b06bacacbd61Automatic Updater expecting to receive answers to those queries that are usually
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User referrals to other name servers.
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User By default <span><strong class="command">host</strong></span> uses UDP when making
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User <code class="option">-T</code> option makes it use a TCP connection when querying
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User the name server. TCP will be automatically selected for queries that
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User require it, such as zone transfer (AXFR) requests.
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User The <code class="option">-4</code> option forces <span><strong class="command">host</strong></span> to only
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User use IPv4 query transport. The <code class="option">-6</code> option forces
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">host</strong></span> to only use IPv6 query transport.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The <code class="option">-t</code> option is used to select the query type.
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User <em class="parameter"><code>type</code></em> can be any recognised query
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein type: CNAME,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein NS, SOA, SIG, KEY, AXFR, etc. When no query type is specified,
71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews <span><strong class="command">host</strong></span> automatically selects an appropriate
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein type. By default it looks for A records, but if the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="option">-C</code> option was given, queries will be made for SOA
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein records, and if <em class="parameter"><code>name</code></em> is a
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User dotted-decimal IPv4
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein 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
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User starting serial number (e.g. -t IXFR=12345678).
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User The time to wait for a reply can be controlled through the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="option">-W</code> and <code class="option">-w</code> options. The
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="option">-W</code> option makes <span><strong class="command">host</strong></span>
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User <em class="parameter"><code>wait</code></em> seconds. If <em class="parameter"><code>wait</code></em>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is less than one, the wait interval is set to one second. When the
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User <code class="option">-w</code> option is used, <span><strong class="command">host</strong></span>
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User effectively wait forever for a reply. The time to wait for a response
983df82baf1d7d0b668c98cf45928a19f175c6e7Tinderbox User will be set to the number of seconds given by the hardware's maximum
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein value for an integer quantity.
fa535fa05f36a1a45027faf9d116cfa3249d9d72Tinderbox User The <code class="option">-s</code> option tells <span><strong class="command">host</strong></span>
fa535fa05f36a1a45027faf9d116cfa3249d9d72Tinderbox User <span class="emphasis"><em>not</em></span> to send the query to the next nameserver
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein if any server responds with a SERVFAIL response, which is the
fa535fa05f36a1a45027faf9d116cfa3249d9d72Tinderbox User reverse of normal stub resolver behaviour.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The <code class="option">-m</code> can be used to set the memory usage debugging
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="parameter"><code>record</code></em>, <em class="parameter"><code>usage</code></em> and
a1ad6695ed6f988406cf155aa26376f84f73bcb9Automatic Updater <em class="parameter"><code>trace</code></em>.
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User If <span><strong class="command">host</strong></span> has been built with IDN (internationalized
44d0f0256fbdce130a18655023c3b06bacacbd61Automatic Updater domain name) support, it can accept and display non-ASCII domain names.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">host</strong></span> appropriately converts character encoding of
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein domain name before sending a request to DNS server or displaying a
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User reply from the server.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein If you'd like to turn off the IDN support for some reason, defines
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the <code class="envar">IDN_DISABLE</code> environment variable.
10b865e9187fc77cae02f106ddcc9e03eecdfe06Tinderbox User The IDN support is disabled if the variable is set when
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">host</strong></span> runs.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><code class="filename">/etc/resolv.conf</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><span class="citerefentry"><span class="refentrytitle">dig</span>(1)</span>,
507151045be68c671ffd4e2f37e17cdfa0376fc4Automatic Updater <span class="citerefentry"><span class="refentrytitle">named</span>(8)</span>.
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