host.docbook revision cf69e3d8b23f473dce7d07a926a3284d614f363b
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt<!ENTITY mdash "—">]>
19c7b1a0293498a3e36692c59646ed6e15ffc8d0Tinderbox User - Copyright (C) 2004, 2005, 2007-2009, 2014, 2015 Internet Systems Consortium, Inc. ("ISC")
dafcb997e390efa4423883dafd100c975c4095d6Mark Andrews - Copyright (C) 2000-2002 Internet Software Consortium.
ec5347e2c775f027573ce5648b910361aa926c01Automatic Updater - Permission to use, copy, modify, and/or distribute this software for any
51eba00c8f281eda4daac725c0c7d1373a93a5aaAndreas Gustafsson - purpose with or without fee is hereby granted, provided that the above
51eba00c8f281eda4daac725c0c7d1373a93a5aaAndreas Gustafsson - copyright notice and this permission notice appear in all copies.
dafcb997e390efa4423883dafd100c975c4095d6Mark Andrews - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
dafcb997e390efa4423883dafd100c975c4095d6Mark Andrews - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
dafcb997e390efa4423883dafd100c975c4095d6Mark Andrews - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
dafcb997e390efa4423883dafd100c975c4095d6Mark Andrews - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
dafcb997e390efa4423883dafd100c975c4095d6Mark Andrews - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
dafcb997e390efa4423883dafd100c975c4095d6Mark Andrews - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
dafcb997e390efa4423883dafd100c975c4095d6Mark Andrews - PERFORMANCE OF THIS SOFTWARE.
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt<!-- Converted by db4-upgrade version 1.0 -->
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="man.host">
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <refentryinfo>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <corpauthor>Internet Systems Consortium, Inc.</corpauthor>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein </refentryinfo>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <refnamediv>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein </refnamediv>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <holder>Internet Systems Consortium, Inc. ("ISC")</holder>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein </copyright>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein </copyright>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <refsynopsisdiv>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <arg choice="opt" rep="norepeat"><option>-aCdlnrsTwv</option></arg>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <arg choice="opt" rep="norepeat"><option>-c <replaceable class="parameter">class</replaceable></option></arg>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <arg choice="opt" rep="norepeat"><option>-N <replaceable class="parameter">ndots</replaceable></option></arg>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <arg choice="opt" rep="norepeat"><option>-R <replaceable class="parameter">number</replaceable></option></arg>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <arg choice="opt" rep="norepeat"><option>-t <replaceable class="parameter">type</replaceable></option></arg>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <arg choice="opt" rep="norepeat"><option>-W <replaceable class="parameter">wait</replaceable></option></arg>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <arg choice="opt" rep="norepeat"><option>-m <replaceable class="parameter">flag</replaceable></option></arg>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <arg choice="opt" rep="norepeat"><option>-4</option></arg>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <arg choice="opt" rep="norepeat"><option>-6</option></arg>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <arg choice="opt" rep="norepeat"><option>-v</option></arg>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <arg choice="opt" rep="norepeat"><option>-V</option></arg>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein </cmdsynopsis>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein </refsynopsisdiv>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <refsection><info><title>DESCRIPTION</title></info>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein is a simple utility for performing DNS lookups.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein It is normally used to convert names to IP addresses and vice versa.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein When no arguments or options are given,
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein prints a short summary of its command line arguments and options.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <para><parameter>name</parameter> is the domain name that is to be
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein up. It can also be a dotted-decimal IPv4 address or a colon-delimited
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein IPv6 address, in which case <command>host</command> will by
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein perform a reverse lookup for that address.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <parameter>server</parameter> is an optional argument which
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein the name or IP address of the name server that <command>host</command>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein should query instead of the server or servers listed in
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </refsection>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <refsection><info><title>OPTIONS</title></info>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <variablelist>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Use IPv4 only for query transport.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Use IPv6 only for query transport.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews "All". The <option>-a</option> option is normally equivalent
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews to <option>-v</option> <option>-t</option> <literal>ANY</literal>.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews It also affects the behaviour of the <option>-l</option>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews list zone option.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <term>-c <replaceable class="parameter">class</replaceable></term>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Query class: This can be used to lookup Hesiod or Chaosnet
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews class resource records. The default class is IN
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Check consistency: <command>host</command> will query the
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews SOA records for zone <parameter>name</parameter> from all
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews the listed authoritative name servers for that zone. The
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews list of name servers is defined by the NS records that are
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews found for the zone.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Print debugging traces.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Equivalent to the <option>-v</option> verbose option.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Use the IP6.INT domain for reverse lookups of IPv6
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews addresses as defined in RFC1886 and deprecated in RFC4159.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews The default is to use IP6.ARPA as specified in RFC3596.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews The <command>host</command> performs a zone transfer of
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews zone <parameter>name</parameter> and prints out the NS,
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Together, the <option>-l</option> <option>-a</option>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews options print all records in the zone.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <term>-N <replaceable class="parameter">ndots</replaceable></term>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews The number of dots that have to be
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews in <parameter>name</parameter> for it to be considered
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews absolute. The default value is that defined using the
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews ndots statement in <filename>/etc/resolv.conf</filename>,
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews or 1 if no ndots statement is present. Names with fewer
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews dots are interpreted as relative names and will be
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews searched for in the domains listed in
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews the <type>search</type> or <type>domain</type> directive
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Non-recursive query:
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Setting this option clears the <type>RD</type> —
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews recursion desired — bit in the query. This should
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews mean that the name server receiving the query will not
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews attempt to resolve <parameter>name</parameter>.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews enables <command>host</command> to mimic the behavior of a
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews name server by making non-recursive queries and expecting
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews to receive answers to those queries that can be
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews referrals to other name servers.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <term>-R <replaceable class="parameter">number</replaceable></term>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Number of retries for UDP queries:
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews If <parameter>number</parameter> is negative or zero, the
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews number of retries will default to 1. The default value is
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews 1, or the value of the <parameter>attempts</parameter>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews option in <filename>/etc/resolv.conf</filename>, if set.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Do <emphasis>not</emphasis> send the query to the next
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews nameserver if any server responds with a SERVFAIL
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews response, which is the reverse of normal stub resolver
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <term>-t <replaceable class="parameter">type</replaceable></term>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews the <parameter>type</parameter> argument can be any
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews recognized query type: CNAME, NS, SOA, TXT, DNSKEY, AXFR, etc.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews When no query type is specified, <command>host</command>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews automatically selects an appropriate query type. By default, it
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews looks for A, AAAA, and MX records.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews If the <option>-C</option> option is given, queries will
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews be made for SOA records.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews If <parameter>name</parameter> is a dotted-decimal IPv4
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews address or colon-delimited IPv6
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews address, <command>host</command> will query for PTR
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews If a query type of IXFR is chosen the starting serial
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews number can be specified by appending an equal followed by
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews the starting serial number
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews (e.g. <option>-t</option> <literal>IXFR=12345678</literal>).
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews By default, <command>host</command> uses UDP when making
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews queries. The <option>-T</option> option makes it use a TCP
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews connection when querying the name server. TCP will be
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews automatically selected for queries that require it, such
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews as zone transfer (AXFR) requests.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <term>-m <replaceable class="parameter">flag</replaceable></term>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Memory usage debugging: the flag can
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews be <parameter>record</parameter>, <parameter>usage</parameter>,
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews or <parameter>trace</parameter>. You can specify
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews the <option>-m</option> option more than once to set
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews multiple flags.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Verbose output.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Equivalent to the <option>-d</option> debug option.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Verbose output can also be enabled by setting
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Print the version number and exit.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Wait forever: the query timeout is set to the maximum possible.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews <term>-W <replaceable class="parameter">wait</replaceable></term>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews Timeout: wait for up to <parameter>wait</parameter>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews seconds for a reply. If <parameter>wait</parameter> is
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews less than one, the wait interval is set to one second.
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews By default, <command>host</command> will wait for 5
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews seconds for UDP responses and 10 seconds for TCP
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews connections. These defaults can be overridden by
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </varlistentry>
cf69e3d8b23f473dce7d07a926a3284d614f363bMark Andrews </variablelist>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt </refsection>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <refsection><info><title>IDN SUPPORT</title></info>
6cf369f528c4acd8182eada41ad83b8d97623db8Mark Andrews If <command>host</command> has been built with IDN (internationalized
30eec077db2bdcb6f2a0dc388a3cdde2ede75ec1Mark Andrews domain name) support, it can accept and display non-ASCII domain names.
6cf369f528c4acd8182eada41ad83b8d97623db8Mark Andrews <command>host</command> appropriately converts character encoding of
6cf369f528c4acd8182eada41ad83b8d97623db8Mark Andrews domain name before sending a request to DNS server or displaying a
6cf369f528c4acd8182eada41ad83b8d97623db8Mark Andrews reply from the server.
6cf369f528c4acd8182eada41ad83b8d97623db8Mark Andrews If you'd like to turn off the IDN support for some reason, defines
6cf369f528c4acd8182eada41ad83b8d97623db8Mark Andrews the <envar>IDN_DISABLE</envar> environment variable.
6cf369f528c4acd8182eada41ad83b8d97623db8Mark Andrews The IDN support is disabled if the variable is set when
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt </refsection>
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt </refsection>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <refentrytitle>dig</refentrytitle><manvolnum>1</manvolnum>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein </citerefentry>,
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <citerefentry>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <refentrytitle>named</refentrytitle><manvolnum>8</manvolnum>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein </citerefentry>.
14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt </refsection>