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5cd4555ad444fd391002ae32450572054369fd42Rob Austein<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
5cd4555ad444fd391002ae32450572054369fd42Rob Austein "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein [<!ENTITY mdash "—">]>
938440694b33cd752e9e4b71a526368b4811c177Tinderbox User - Copyright (C) 2004, 2005, 2007-2009, 2014 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.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <refentryinfo>
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>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <cmdsynopsis>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <arg><option>-c <replaceable class="parameter">class</replaceable></option></arg>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <arg><option>-N <replaceable class="parameter">ndots</replaceable></option></arg>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <arg><option>-R <replaceable class="parameter">number</replaceable></option></arg>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <arg><option>-t <replaceable class="parameter">type</replaceable></option></arg>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <arg><option>-W <replaceable class="parameter">wait</replaceable></option></arg>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <arg><option>-m <replaceable class="parameter">flag</replaceable></option></arg>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein </cmdsynopsis>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein </refsynopsisdiv>
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
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein The <option>-a</option> (all) option is equivalent to setting the
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <option>-v</option> option and asking <command>host</command> to make
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein a query of type ANY.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein When the <option>-C</option> option is used, <command>host</command>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein will attempt to display the SOA records for zone
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein authoritative name
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein servers for that zone. The list of name servers is defined by the NS
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein records that are found for the zone.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein The <option>-c</option> option instructs to make a DNS query of class
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <parameter>class</parameter>. This can be used to lookup
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein Chaosnet class resource records. The default class is IN (Internet).
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein Verbose output is generated by <command>host</command> when
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <option>-d</option> or <option>-v</option> option is used. The two
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein options are equivalent. They have been provided for backwards
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein compatibility. In previous versions, the <option>-d</option> option
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein switched on debugging traces and <option>-v</option> enabled verbose
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein List mode is selected by the <option>-l</option> option. This makes
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <command>host</command> perform a zone transfer for zone
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <parameter>name</parameter>. Transfer the zone printing out
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein and address records (A/AAAA). If combined with <option>-a</option>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein all records will be printed.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein option specifies that reverse lookups of IPv6 addresses should
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein use the IP6.INT domain as defined in RFC1886.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein The default is to use IP6.ARPA.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein The <option>-N</option> option sets the number of dots that have to be
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein in <parameter>name</parameter> for it to be considered
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein absolute. The
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein default value is that defined using the ndots statement in
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <filename>/etc/resolv.conf</filename>, or 1 if no ndots
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein statement is
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein present. Names with fewer dots are interpreted as relative names and
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein will be searched for in the domains listed in the <type>search</type>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein The number of UDP retries for a lookup can be changed with the
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <option>-R</option> option. <parameter>number</parameter>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein how many times <command>host</command> will repeat a query
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein not get answered. The default number of retries is 1. If
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <parameter>number</parameter> is negative or zero, the
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein retries will default to 1.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein Non-recursive queries can be made via the <option>-r</option> option.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein Setting this option clears the <type>RD</type> — recursion
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein desired — bit in the query which <command>host</command> makes.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein This should mean that the name server receiving the query will not
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein attempt to resolve <parameter>name</parameter>. The
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <option>-r</option> option enables <command>host</command>
561a29af8c54a216e7d30b5b4f6e0d21661654ecMark Andrews the behavior of a name server by making non-recursive queries and
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein expecting to receive answers to those queries that are usually
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein referrals to other name servers.
f9f11eb54be19b7deedf3978496f71d81432a5eeJeremy Reed By default, <command>host</command> uses UDP when making
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein queries. The
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <option>-T</option> option makes it use a TCP connection when querying
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein the name server. TCP will be automatically selected for queries that
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein require it, such as zone transfer (AXFR) requests.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein The <option>-4</option> option forces <command>host</command> to only
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein use IPv4 query transport. The <option>-6</option> option forces
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <command>host</command> to only use IPv6 query transport.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein The <option>-t</option> option is used to select the query type.
561a29af8c54a216e7d30b5b4f6e0d21661654ecMark Andrews <parameter>type</parameter> can be any recognized query
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein type: CNAME,
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein NS, SOA, SIG, KEY, AXFR, etc. When no query type is specified,
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <command>host</command> automatically selects an appropriate
f9f11eb54be19b7deedf3978496f71d81432a5eeJeremy Reed type. By default, it looks for A, AAAA, and MX records, but if the
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <option>-C</option> option was given, queries will be made for SOA
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein records, and if <parameter>name</parameter> is a
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein dotted-decimal IPv4
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein address or colon-delimited IPv6 address, <command>host</command> will
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein query for PTR records. If a query type of IXFR is chosen the starting
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein serial number can be specified by appending an equal followed by the
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein starting serial number (e.g. -t IXFR=12345678).
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein The time to wait for a reply can be controlled through the
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <option>-W</option> and <option>-w</option> options. The
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <option>-W</option> option makes <command>host</command>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <parameter>wait</parameter> seconds. If <parameter>wait</parameter>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein is less than one, the wait interval is set to one second. When the
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <option>-w</option> option is used, <command>host</command>
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein effectively wait forever for a reply. The time to wait for a response
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein will be set to the number of seconds given by the hardware's maximum
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein value for an integer quantity.
3d711f2f75cb9a9ddcbf1fca9b2de192e75340e6Mark Andrews The <option>-s</option> option tells <command>host</command>
3d711f2f75cb9a9ddcbf1fca9b2de192e75340e6Mark Andrews <emphasis>not</emphasis> to send the query to the next nameserver
3d711f2f75cb9a9ddcbf1fca9b2de192e75340e6Mark Andrews if any server responds with a SERVFAIL response, which is the
561a29af8c54a216e7d30b5b4f6e0d21661654ecMark Andrews reverse of normal stub resolver behavior.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein The <option>-m</option> can be used to set the memory usage debugging
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein <parameter>record</parameter>, <parameter>usage</parameter> and
67d01dcacb2051a03377c8ec5c0e36604c17aea5Evan Hunt The <option>-V</option> option causes <command>host</command>
67d01dcacb2051a03377c8ec5c0e36604c17aea5Evan Hunt to print the version number and exit.
6cf369f528c4acd8182eada41ad83b8d97623db8Mark Andrews If <command>host</command> has been built with IDN (internationalized
6cf369f528c4acd8182eada41ad83b8d97623db8Mark 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
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>.
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein - Local variables:
268a4475065fe6a8cd7cc707820982cf5e98f430Rob Austein - mode: sgml