host.docbook revision 3001a1b4e6298466882a4147307b4c28a3b08f91
990d0e893f5b70e735cdf990af66e9ec6e91fa78Tinderbox User<!ENTITY mdash "—">]>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews - Copyright (C) 2000-2002, 2004, 2005, 2007-2009, 2014-2016 Internet Systems Consortium, Inc. ("ISC")
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews - This Source Code Form is subject to the terms of the Mozilla Public
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews - License, v. 2.0. If a copy of the MPL was not distributed with this
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews - file, You can obtain one at http://mozilla.org/MPL/2.0/.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<!-- Converted by db4-upgrade version 1.0 -->
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<refentry xmlns:db="http://docbook.org/ns/docbook" version="5.0" xml:id="man.host">
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <refentryinfo>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <corpauthor>Internet Systems Consortium, Inc.</corpauthor>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews </refentryinfo>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <refnamediv>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews </refnamediv>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <holder>Internet Systems Consortium, Inc. ("ISC")</holder>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews </copyright>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <refsynopsisdiv>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <arg choice="opt" rep="norepeat"><option>-aCdlnrsTUwv</option></arg>
61ab11c0ec845606f85452b2c9f2e223772aae00Tinderbox User <arg choice="opt" rep="norepeat"><option>-c <replaceable class="parameter">class</replaceable></option></arg>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <arg choice="opt" rep="norepeat"><option>-N <replaceable class="parameter">ndots</replaceable></option></arg>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <arg choice="opt" rep="norepeat"><option>-R <replaceable class="parameter">number</replaceable></option></arg>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <arg choice="opt" rep="norepeat"><option>-t <replaceable class="parameter">type</replaceable></option></arg>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <arg choice="opt" rep="norepeat"><option>-W <replaceable class="parameter">wait</replaceable></option></arg>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <arg choice="opt" rep="norepeat"><option>-m <replaceable class="parameter">flag</replaceable></option></arg>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <arg choice="opt" rep="norepeat"><option>-4</option></arg>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <arg choice="opt" rep="norepeat"><option>-6</option></arg>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <arg choice="opt" rep="norepeat"><option>-v</option></arg>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <arg choice="opt" rep="norepeat"><option>-V</option></arg>
b2f07642fd712c8fda81a116bcdde229ab291f33Tinderbox User <arg choice="opt" rep="norepeat">server</arg>
b2f07642fd712c8fda81a116bcdde229ab291f33Tinderbox User </cmdsynopsis>
b2f07642fd712c8fda81a116bcdde229ab291f33Tinderbox User </refsynopsisdiv>
b2f07642fd712c8fda81a116bcdde229ab291f33Tinderbox User <refsection><info><title>DESCRIPTION</title></info>
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 prints a short summary of its command line arguments and options.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <para><parameter>name</parameter> 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 <command>host</command> will by
61ab11c0ec845606f85452b2c9f2e223772aae00Tinderbox User perform a reverse lookup for that address.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <parameter>server</parameter> is an optional argument which
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews the name or IP address of the name server that <command>host</command>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews should query instead of the server or servers listed in
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews </refsection>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <refsection><info><title>OPTIONS</title></info>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <variablelist>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <varlistentry>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews Use IPv4 only for query transport.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews </varlistentry>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <varlistentry>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews Use IPv6 only for query transport.
b2f07642fd712c8fda81a116bcdde229ab291f33Tinderbox User </varlistentry>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <varlistentry>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews "All". The <option>-a</option> option is normally equivalent
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews to <option>-v -t <literal>ANY</literal></option>.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews It also affects the behaviour of the <option>-l</option>
d3ddafd7469d1f3430ccd1b0fe0d13ccbbaf5debTinderbox User list zone option.
d3ddafd7469d1f3430ccd1b0fe0d13ccbbaf5debTinderbox User </varlistentry>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <varlistentry>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <term>-c <replaceable class="parameter">class</replaceable></term>
c247e3f281613fabe1af362e9f3157e35ebbe52cMark Andrews Query class: This can be used to lookup HS (Hesiod) or CH
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews (Chaosnet) class resource records. The default class is IN
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews </varlistentry>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <varlistentry>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews Check consistency: <command>host</command> will query the
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews SOA records for zone <parameter>name</parameter> from all
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews the listed authoritative name servers for that zone. The
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews list of name servers is defined by the NS records that are
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews found for the zone.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Print debugging traces.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews Equivalent to the <option>-v</option> verbose option.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Use the IP6.INT domain for reverse lookups of IPv6
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User addresses as defined in RFC1886 and deprecated in RFC4159.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User The default is to use IP6.ARPA as specified in RFC3596.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
4f9cb7bd58e2c0a7407fee3758ea265aee329ac6Tinderbox User The <command>host</command> command performs a zone transfer of
4f9cb7bd58e2c0a7407fee3758ea265aee329ac6Tinderbox User zone <parameter>name</parameter> and prints out the NS,
4f9cb7bd58e2c0a7407fee3758ea265aee329ac6Tinderbox User options print all records in the zone.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <term>-N <replaceable class="parameter">ndots</replaceable></term>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User The number of dots that have to be
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User in <parameter>name</parameter> for it to be considered
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User absolute. The default value is that defined using the
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User ndots statement in <filename>/etc/resolv.conf</filename>,
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User or 1 if no ndots statement is present. Names with fewer
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User dots are interpreted as relative names and will be
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User searched for in the domains listed in
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User the <type>search</type> or <type>domain</type> directive
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Non-recursive query:
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Setting this option clears the RD (recursion desired) bit
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User in the query. This should mean that the name server
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User receiving the query will not attempt to
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User enables <command>host</command> to mimic the behavior of a
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User name server by making non-recursive queries and expecting
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User to receive answers to those queries that can be
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User referrals to other name servers.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <term>-R <replaceable class="parameter">number</replaceable></term>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Number of retries for UDP queries:
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User If <parameter>number</parameter> is negative or zero, the
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User number of retries will default to 1. The default value is
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User 1, or the value of the <parameter>attempts</parameter>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User option in <filename>/etc/resolv.conf</filename>, if set.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Do <emphasis>not</emphasis> send the query to the next
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User nameserver if any server responds with a SERVFAIL
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User response, which is the reverse of normal stub resolver
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <term>-t <replaceable class="parameter">type</replaceable></term>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User The <parameter>type</parameter> argument can be any
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User recognized query type: CNAME, NS, SOA, TXT, DNSKEY, AXFR, etc.
f2016fcecf098726740507a5522dca04c49aeb82Tinderbox User When no query type is specified, <command>host</command>
f2016fcecf098726740507a5522dca04c49aeb82Tinderbox User automatically selects an appropriate query type. By default, it
f2016fcecf098726740507a5522dca04c49aeb82Tinderbox User looks for A, AAAA, and MX records.
f2016fcecf098726740507a5522dca04c49aeb82Tinderbox User If the <option>-C</option> option is given, queries will
f2016fcecf098726740507a5522dca04c49aeb82Tinderbox User be made for SOA records.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User If <parameter>name</parameter> is a dotted-decimal IPv4
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User address or colon-delimited IPv6
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User address, <command>host</command> will query for PTR
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User If a query type of IXFR is chosen the starting serial
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User number can be specified by appending an equal followed by
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User the starting serial number
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User (like <option>-t <literal>IXFR=12345678</literal></option>).
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User By default, <command>host</command> uses UDP when making
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User queries. The <option>-T</option> option makes it use a TCP
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User connection when querying the name server. TCP will be
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User automatically selected for queries that require it, such
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User as zone transfer (AXFR) requests. Type ANY queries default
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User to TCP but can be forced to UDP initially using <option>-U</option>.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <term>-m <replaceable class="parameter">flag</replaceable></term>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Memory usage debugging: the flag can
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User be <parameter>record</parameter>, <parameter>usage</parameter>,
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User or <parameter>trace</parameter>. You can specify
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User the <option>-m</option> option more than once to set
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User multiple flags.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Verbose output.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Equivalent to the <option>-d</option> debug option.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Verbose output can also be enabled by setting
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Print the version number and exit.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Wait forever: The query timeout is set to the maximum possible.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <term>-W <replaceable class="parameter">wait</replaceable></term>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User Timeout: Wait for up to <parameter>wait</parameter>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User seconds for a reply. If <parameter>wait</parameter> is
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User less than one, the wait interval is set to one second.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User By default, <command>host</command> will wait for 5
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User seconds for UDP responses and 10 seconds for TCP
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User connections. These defaults can be overridden by
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </varlistentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </variablelist>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </refsection>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <refsection><info><title>IDN SUPPORT</title></info>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User If <command>host</command> has been built with IDN (internationalized
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User domain name) support, it can accept and display non-ASCII domain names.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <command>host</command> appropriately converts character encoding of
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User domain name before sending a request to DNS server or displaying a
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User reply from the server.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User If you'd like to turn off the IDN support for some reason, defines
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User the <envar>IDN_DISABLE</envar> environment variable.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User The IDN support is disabled if the variable is set when
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </refsection>
ccee3948124ab4c8bc3afa4369177913edb1fca2Tinderbox User <refsection><info><title>FILES</title></info>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </refsection>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <refsection><info><title>SEE ALSO</title></info>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <refentrytitle>dig</refentrytitle><manvolnum>1</manvolnum>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </citerefentry>,
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <citerefentry>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User <refentrytitle>named</refentrytitle><manvolnum>8</manvolnum>
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </citerefentry>.
0ccb0e98c77a9b9636a036f8f64f5679a430aaf4Tinderbox User </refsection>