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11e9368a226272085c337e9e74b79808c16fbdbaTinderbox User - Copyright (C) 2004-2015 Internet Systems Consortium, Inc. ("ISC")
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews - Copyright (C) 2000-2003 Internet Software Consortium.
4a14ce5ba00ab7bc55c99ffdcf59c7a4ab902721Automatic Updater - Permission to use, copy, modify, and/or distribute this software for any
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews - purpose with or without fee is hereby granted, provided that the above
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews - copyright notice and this permission notice appear in all copies.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
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5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<a name="man.host"></a><div class="titlepage"></div>
b46346eb3026ba4bebc093bc93cfe159131e541eTinderbox 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>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<p><span><strong class="command">host</strong></span>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews is a simple utility for performing DNS lookups.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews It is normally used to convert names to IP addresses and vice versa.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews When no arguments or options are given,
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <span><strong class="command">host</strong></span>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews prints a short summary of its command line arguments and options.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<p><em class="parameter"><code>name</code></em> is the domain name that is to be
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews up. It can also be a dotted-decimal IPv4 address or a colon-delimited
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews IPv6 address, in which case <span><strong class="command">host</strong></span> will by
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews perform a reverse lookup for that address.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <em class="parameter"><code>server</code></em> is an optional argument which
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews the name or IP address of the name server that <span><strong class="command">host</strong></span>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews should query instead of the server or servers listed in
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="filename">/etc/resolv.conf</code>.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews The <code class="option">-a</code> (all) option is equivalent to setting the
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="option">-v</code> option and asking <span><strong class="command">host</strong></span> to make
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews a query of type ANY.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews When the <code class="option">-C</code> option is used, <span><strong class="command">host</strong></span>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews will attempt to display the SOA records for zone
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <em class="parameter"><code>name</code></em> from all the listed
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews authoritative name
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews servers for that zone. The list of name servers is defined by the NS
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews records that are found for the zone.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews The <code class="option">-c</code> option instructs to make a DNS query of class
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <em class="parameter"><code>class</code></em>. This can be used to lookup
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews Chaosnet class resource records. The default class is IN (Internet).
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews Verbose output is generated by <span><strong class="command">host</strong></span> when
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="option">-d</code> or <code class="option">-v</code> option is used. The two
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews options are equivalent. They have been provided for backwards
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews compatibility. In previous versions, the <code class="option">-d</code> option
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews switched on debugging traces and <code class="option">-v</code> enabled verbose
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User output. Verbose output can also be enabled by setting the
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User <em class="parameter"><code>debug</code></em> option in
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User <code class="filename">/etc/resolv.conf</code>.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews List mode is selected by the <code class="option">-l</code> option. This makes
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <span><strong class="command">host</strong></span> perform a zone transfer for zone
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <em class="parameter"><code>name</code></em>. Transfer the zone printing out
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews and address records (A/AAAA). If combined with <code class="option">-a</code>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews all records will be printed.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews option specifies that reverse lookups of IPv6 addresses should
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews use the IP6.INT domain as defined in RFC1886.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews The default is to use IP6.ARPA.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews The <code class="option">-N</code> option sets the number of dots that have to be
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews in <em class="parameter"><code>name</code></em> for it to be considered
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews absolute. The
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews default value is that defined using the ndots statement in
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="filename">/etc/resolv.conf</code>, or 1 if no ndots
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews statement is
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews present. Names with fewer dots are interpreted as relative names and
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews will be searched for in the domains listed in the <span class="type">search</span>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews or <span class="type">domain</span> directive in
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="filename">/etc/resolv.conf</code>.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews The number of UDP retries for a lookup can be changed with the
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="option">-R</code> option. <em class="parameter"><code>number</code></em>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews how many times <span><strong class="command">host</strong></span> will repeat a query
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User not get answered. If
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <em class="parameter"><code>number</code></em> is negative or zero, the
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User retries will default to 1. The default value is 1, or
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User the value of the <em class="parameter"><code>attempts</code></em> option in
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User <code class="filename">/etc/resolv.conf</code>, if set.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews Non-recursive queries can be made via the <code class="option">-r</code> option.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews Setting this option clears the <span class="type">RD</span> — recursion
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews desired — bit in the query which <span><strong class="command">host</strong></span> makes.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews This should mean that the name server receiving the query will not
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews attempt to resolve <em class="parameter"><code>name</code></em>. The
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="option">-r</code> option enables <span><strong class="command">host</strong></span>
d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews the behavior of a name server by making non-recursive queries and
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews expecting to receive answers to those queries that are usually
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews referrals to other name servers.
9fbbfb5757a1e3e86d7dea62c4e63ffc2303ca2bAutomatic Updater By default, <span><strong class="command">host</strong></span> uses UDP when making
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews queries. The
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="option">-T</code> option makes it use a TCP connection when querying
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews the name server. TCP will be automatically selected for queries that
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews require it, such as zone transfer (AXFR) requests.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews The <code class="option">-4</code> option forces <span><strong class="command">host</strong></span> to only
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews use IPv4 query transport. The <code class="option">-6</code> option forces
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <span><strong class="command">host</strong></span> to only use IPv6 query transport.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews The <code class="option">-t</code> option is used to select the query type.
d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews <em class="parameter"><code>type</code></em> can be any recognized query
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews type: CNAME,
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews NS, SOA, SIG, KEY, AXFR, etc. When no query type is specified,
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <span><strong class="command">host</strong></span> automatically selects an appropriate
9fbbfb5757a1e3e86d7dea62c4e63ffc2303ca2bAutomatic Updater type. By default, it looks for A, AAAA, and MX records, but if the
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="option">-C</code> option was given, queries will be made for SOA
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews records, and if <em class="parameter"><code>name</code></em> is a
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews dotted-decimal IPv4
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews address or colon-delimited IPv6 address, <span><strong class="command">host</strong></span> will
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews query for PTR records. If a query type of IXFR is chosen the starting
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews serial number can be specified by appending an equal followed by the
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews starting serial number (e.g. -t IXFR=12345678).
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews The time to wait for a reply can be controlled through the
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="option">-W</code> and <code class="option">-w</code> options. The
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="option">-W</code> option makes <span><strong class="command">host</strong></span>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <em class="parameter"><code>wait</code></em> seconds. If <em class="parameter"><code>wait</code></em>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews is less than one, the wait interval is set to one second. When the
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="option">-w</code> option is used, <span><strong class="command">host</strong></span>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews effectively wait forever for a reply. The time to wait for a response
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews will be set to the number of seconds given by the hardware's maximum
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User value for an integer quantity. By default, <span><strong class="command">host</strong></span>
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User will wait for 5 seconds for UDP responses and 10 seconds for TCP
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User connections. These defaults can be overridden by the
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User <em class="parameter"><code>timeout</code></em> option in
f39512a917cdd06c611d366603374f6ef570c80eTinderbox User <code class="filename">/etc/resolv.conf</code>.
a057e8e33baa5fa369be28a9680585200ce3ff73Mark Andrews The <code class="option">-s</code> option tells <span><strong class="command">host</strong></span>
a057e8e33baa5fa369be28a9680585200ce3ff73Mark Andrews <span class="emphasis"><em>not</em></span> to send the query to the next nameserver
a057e8e33baa5fa369be28a9680585200ce3ff73Mark Andrews if any server responds with a SERVFAIL response, which is the
d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews reverse of normal stub resolver behavior.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews The <code class="option">-m</code> can be used to set the memory usage debugging
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <em class="parameter"><code>record</code></em>, <em class="parameter"><code>usage</code></em> and
b46346eb3026ba4bebc093bc93cfe159131e541eTinderbox User The <code class="option">-V</code> option causes <span><strong class="command">host</strong></span>
b46346eb3026ba4bebc093bc93cfe159131e541eTinderbox User to print the version number and exit.
057cafaa3df7be7a6dcca71fbaf8fb498fd83518Mark Andrews If <span><strong class="command">host</strong></span> has been built with IDN (internationalized
057cafaa3df7be7a6dcca71fbaf8fb498fd83518Mark Andrews domain name) support, it can accept and display non-ASCII domain names.
057cafaa3df7be7a6dcca71fbaf8fb498fd83518Mark Andrews <span><strong class="command">host</strong></span> appropriately converts character encoding of
057cafaa3df7be7a6dcca71fbaf8fb498fd83518Mark Andrews domain name before sending a request to DNS server or displaying a
057cafaa3df7be7a6dcca71fbaf8fb498fd83518Mark Andrews reply from the server.
057cafaa3df7be7a6dcca71fbaf8fb498fd83518Mark Andrews If you'd like to turn off the IDN support for some reason, defines
057cafaa3df7be7a6dcca71fbaf8fb498fd83518Mark Andrews the <code class="envar">IDN_DISABLE</code> environment variable.
057cafaa3df7be7a6dcca71fbaf8fb498fd83518Mark Andrews The IDN support is disabled if the variable is set when
057cafaa3df7be7a6dcca71fbaf8fb498fd83518Mark Andrews <span><strong class="command">host</strong></span> runs.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<p><code class="filename">/etc/resolv.conf</code>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<p><span class="citerefentry"><span class="refentrytitle">dig</span>(1)</span>,
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <span class="citerefentry"><span class="refentrytitle">named</span>(8)</span>.
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30c0c7470d5bfabd8f43c563f4eca636d06cc484Tinderbox User<p style="text-align: center;">BIND 9.11.0pre-alpha</p>