host.docbook revision 893612590b1cc64e0c989b8b6e1ff595aea7e48a
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN">
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - Copyright (C) 2000, 2001 Internet Software Consortium.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - Permission to use, copy, modify, and distribute this software for any
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - purpose with or without fee is hereby granted, provided that the above
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - copyright notice and this permission notice appear in all copies.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass - WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<!-- $Id: host.docbook,v 1.2 2001/06/08 17:18:13 gson Exp $ -->
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<refentryinfo>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass</refentryinfo>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass</refnamediv>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<refsynopsisdiv>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<cmdsynopsis>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass <arg><option>-c <replaceable class="parameter">class</replaceable></option></arg>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass <arg><option>-N <replaceable class="parameter">ndots</replaceable></option></arg>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass <arg><option>-R <replaceable class="parameter">number</replaceable></option></arg>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass <arg><option>-t <replaceable class="parameter">type</replaceable></option></arg>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass <arg><option>-W <replaceable class="parameter">wait</replaceable></option></arg>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass</cmdsynopsis>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass</refsynopsisdiv>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassis a simple utility for performing DNS lookups.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassIt is normally used to convert names to IP addresses and vice versa.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassWhen no arguments or options are given,
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassprints a short summary of its command line arguments and options.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<parameter>name</parameter> is the domain name that is to be looked
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassup. It can also be a dotted-decimal IPv4 address or a colon-delimited
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassIPv6 address, in which case <command>host</command> will by default
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassperform a reverse lookup for that address.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<parameter>server</parameter> is an optional argument which is either
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassthe name or IP address of the name server that <command>host</command>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassshould query instead of the server or servers listed in
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassThe <option>-a</option> (all) option is equivalent to setting the
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<option>-v</option> option and asking <command>host</command> to make
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassa query of type ANY.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassWhen the <option>-C</option> option is used, <command>host</command>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glasswill attempt to display the SOA records for zone
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<parameter>name</parameter> from all the listed authoritative name
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassservers for that zone. The list of name servers is defined by the NS
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassrecords that are found for the zone.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassThe <option>-c</option> option instructs to make a DNS query of class
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<parameter>class</parameter>. This can be used to lookup Hesiod or
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassChaosnet class resource records. The default class is IN (Internet).
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassVerbose output is generated by <command>host</command> when the
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<option>-d</option> or <option>-v</option> option is used. The two
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassoptions are equivalent. They have been provided for backwards
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glasscompatibility. In previous versions, the <option>-d</option> option
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassswitched on debugging traces and <option>-v</option> enabled verbose
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassList mode is selected by the <option>-l</option> option. This makes
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<command>host</command> perform a zone transfer for zone
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<parameter>name</parameter>. The argument is provided for
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glasscompatibility with older implemementations. This option is equivalent
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassto making a query of type AXFR.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassoption specifies that reverse lookups of IPv6 addresses should
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassuse the IP6.INT domain and "nibble" labels as defined in RFC1886.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassThe default is to use IP6.ARPA and binary labels as defined in RFC2874.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassThe <option>-N</option> option sets the number of dots that have to be
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassin <parameter>name</parameter> for it to be considered absolute. The
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassdefault value is that defined using the ndots statement in
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<filename>/etc/resolv.conf</filename>, or 1 if no ndots statement is
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glasspresent. Names with fewer dots are interpreted as relative names and
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glasswill be searched for in the domains listed in the <type>search</type>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassThe number of UDP retries for a lookup can be changed with the
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<option>-R</option> option. <parameter>number</parameter> indicates
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glasshow many times <command>host</command> will repeat a query that does
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassnot get answered. The default number of retries is 1. If
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<parameter>number</parameter> is negative or zero, the number of
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassretries will default to 1.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassNon-recursive queries can be made via the <option>-r</option> option.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassSetting this option clears the <type>RD</type> — recursion
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassdesired — bit in the query which <command>host</command> makes.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassThis should mean that the name server receiving the query will not
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassattempt to resolve <parameter>name</parameter>. The
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<option>-r</option> option enables <command>host</command> to mimic
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassthe behaviour of a name server by making non-recursive queries and
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassexpecting to receive answers to those queries that are usually
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassreferrals to other name servers.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassBy default <command>host</command> uses UDP when making queries. The
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<option>-T</option> option makes it use a TCP connection when querying
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassthe name server. TCP will be automatically selected for queries that
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassrequire it, such as zone transfer (AXFR) requests.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassThe <option>-t</option> option is used to select the query type.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<parameter>type</parameter> can be any recognised query type: CNAME,
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassNS, SOA, SIG, KEY, AXFR, etc. When no query type is specified,
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<command>host</command> automatically selects an appropriate query
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glasstype. By default it looks for A records, but if the
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<option>-C</option> option was given, queries will be made for SOA
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassrecords, and if <parameter>name</parameter> is a dotted-decimal IPv4
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassaddress or colon-delimited IPv6 address, <command>host</command> will
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassquery for PTR records.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav GlassThe time to wait for a reply can be controlled through the
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<option>-W</option> and <option>-w</option> options. The
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<option>-W</option> option makes <command>host</command> wait for
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<parameter>wait</parameter> seconds. If <parameter>wait</parameter>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassis less than one, the wait interval is set to one second. When the
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<option>-w</option> option is used, <command>host</command> will
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glasseffectively wait forever for a reply. The time to wait for a response
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glasswill be set to the number of seconds given by the hardware's maximum
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glassvalue for an integer quantity.
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<citerefentry>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<refentrytitle>dig</refentrytitle><manvolnum>1</manvolnum>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass</citerefentry>,
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<citerefentry>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass<refentrytitle>named</refentrytitle><manvolnum>8</manvolnum>
76ca635d61eb3f9fb7c9d788a44fa8b1690aa138Dav Glass</citerefentry>.