d6fa26d0adaec6c910115be34fe7a5a5f402c14fMark Andrews<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.0//EN"

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein "http://www.oasis-open.org/docbook/xml/4.0/docbookx.dtd"

5347c0fcb04eaea19d9f39795646239f487c6207Tinderbox User [<!ENTITY mdash "&#8212;">]>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews<refentry id="man.host">

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refentryinfo>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <date>Jun 30, 2000</date>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </refentryinfo>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refmeta>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refentrytitle>host</refentrytitle>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <manvolnum>1</manvolnum>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refmiscinfo>BIND9</refmiscinfo>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </refmeta>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User <refnamediv>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User <refname>host</refname>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refpurpose>DNS lookup utility</refpurpose>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </refnamediv>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User

af40ebed6257e4ac1996144530b3de317cf4da11Tinderbox User <docinfo>

af40ebed6257e4ac1996144530b3de317cf4da11Tinderbox User <copyright>

af40ebed6257e4ac1996144530b3de317cf4da11Tinderbox User <year>2004</year>

af40ebed6257e4ac1996144530b3de317cf4da11Tinderbox User <year>2005</year>

af40ebed6257e4ac1996144530b3de317cf4da11Tinderbox User <holder>Internet Systems Consortium, Inc. ("ISC")</holder>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </copyright>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <copyright>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User <year>2000</year>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2001</year>

af40ebed6257e4ac1996144530b3de317cf4da11Tinderbox User <year>2002</year>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User <holder>Internet Software Consortium.</holder>

71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews </copyright>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </docinfo>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews <refsynopsisdiv>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <cmdsynopsis>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User <command>host</command>

71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews <arg><option>-aCdlnrTwv</option></arg>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <arg><option>-c <replaceable class="parameter">class</replaceable></option></arg>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <arg><option>-N <replaceable class="parameter">ndots</replaceable></option></arg>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <arg><option>-R <replaceable class="parameter">number</replaceable></option></arg>

71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews <arg><option>-t <replaceable class="parameter">type</replaceable></option></arg>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <arg><option>-W <replaceable class="parameter">wait</replaceable></option></arg>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <arg><option>-m <replaceable class="parameter">flag</replaceable></option></arg>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <arg><option>-4</option></arg>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User <arg><option>-6</option></arg>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User <arg choice="req">name</arg>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <arg choice="opt">server</arg>

af40ebed6257e4ac1996144530b3de317cf4da11Tinderbox User </cmdsynopsis>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User </refsynopsisdiv>

71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refsect1>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <title>DESCRIPTION</title>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para><command>host</command>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is a simple utility for performing DNS lookups.

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User It is normally used to convert names to IP addresses and vice versa.

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User When no arguments or options are given,

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <command>host</command>

af40ebed6257e4ac1996144530b3de317cf4da11Tinderbox User prints a short summary of its command line arguments and options.

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User </para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <para><parameter>name</parameter> is the domain name that is to be

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein looked

71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews up. It can also be a dotted-decimal IPv4 address or a colon-delimited

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein IPv6 address, in which case <command>host</command> will by

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein default

14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt perform a reverse lookup for that address.

14a656f94b1fd0ababd84a772228dfa52276ba15Evan Hunt <parameter>server</parameter> is an optional argument which

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is either

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the name or IP address of the name server that <command>host</command>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein should query instead of the server or servers listed in

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <filename>/etc/resolv.conf</filename>.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The <option>-a</option> (all) option is equivalent to setting the

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <option>-v</option> option and asking <command>host</command> to make

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein a query of type ANY.

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User </para>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para>

af40ebed6257e4ac1996144530b3de317cf4da11Tinderbox User When the <option>-C</option> option is used, <command>host</command>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User will attempt to display the SOA records for zone

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>name</parameter> from all the listed

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein authoritative name

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein servers for that zone. The list of name servers is defined by the NS

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein records that are found for the zone.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The <option>-c</option> option instructs to make a DNS query of class

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>class</parameter>. This can be used to lookup

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Hesiod or

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Chaosnet class resource records. The default class is IN (Internet).

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User <para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Verbose output is generated by <command>host</command> when

af40ebed6257e4ac1996144530b3de317cf4da11Tinderbox User the

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User <option>-d</option> or <option>-v</option> option is used. The two

71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews options are equivalent. They have been provided for backwards

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein compatibility. In previous versions, the <option>-d</option> option

5d564da348e890e42f63eebf2dced9a05b41f4fbTinderbox User switched on debugging traces and <option>-v</option> enabled verbose

a1ad6695ed6f988406cf155aa26376f84f73bcb9Automatic Updater output.

a1ad6695ed6f988406cf155aa26376f84f73bcb9Automatic Updater </para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein List mode is selected by the <option>-l</option> option. This makes

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <command>host</command> perform a zone transfer for zone

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User <parameter>name</parameter>. Transfer the zone printing out

fd2597f75693a2279fdf588bd40dfe2407c42028Tinderbox User the NS, PTR

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and address records (A/AAAA). If combined with <option>-a</option>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein all records will be printed.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The <option>-i</option>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein option specifies that reverse lookups of IPv6 addresses should

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein use the IP6.INT domain as defined in RFC1886.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The default is to use IP6.ARPA.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The <option>-N</option> option sets the number of dots that have to be

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein in <parameter>name</parameter> for it to be considered

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein absolute. The

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein default value is that defined using the ndots statement in

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <filename>/etc/resolv.conf</filename>, or 1 if no ndots

1ca759b3f5c0672b2a66bc02288fe010cabbfe37Tinderbox User statement is

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein present. Names with fewer dots are interpreted as relative names and

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein will be searched for in the domains listed in the <type>search</type>

or <type>domain</type> directive in

<filename>/etc/resolv.conf</filename>.

</para>

<para>

The number of UDP retries for a lookup can be changed with the

<option>-R</option> option. <parameter>number</parameter>

indicates

how many times <command>host</command> will repeat a query

that does

not get answered. The default number of retries is 1. If

<parameter>number</parameter> is negative or zero, the

number of

retries will default to 1.

</para>

<para>

Non-recursive queries can be made via the <option>-r</option> option.

Setting this option clears the <type>RD</type> &mdash; recursion

desired &mdash; bit in the query which <command>host</command> makes.

This should mean that the name server receiving the query will not

attempt to resolve <parameter>name</parameter>. The

<option>-r</option> option enables <command>host</command>

to mimic

the behaviour of a name server by making non-recursive queries and

expecting to receive answers to those queries that are usually

referrals to other name servers.

</para>

<para>

By default <command>host</command> uses UDP when making

queries. The

<option>-T</option> option makes it use a TCP connection when querying

the name server. TCP will be automatically selected for queries that

require it, such as zone transfer (AXFR) requests.

</para>

<para>

The <option>-4</option> option forces <command>host</command> to only

use IPv4 query transport. The <option>-6</option> option forces

<command>host</command> to only use IPv6 query transport.

</para>

<para>

The <option>-t</option> option is used to select the query type.

<parameter>type</parameter> can be any recognised query

type: CNAME,

NS, SOA, SIG, KEY, AXFR, etc. When no query type is specified,

<command>host</command> automatically selects an appropriate

query

type. By default it looks for A records, but if the

<option>-C</option> option was given, queries will be made for SOA

records, and if <parameter>name</parameter> is a

dotted-decimal IPv4

address or colon-delimited IPv6 address, <command>host</command> will

query for PTR records. If a query type of IXFR is chosen the starting

serial number can be specified by appending an equal followed by the

starting serial number (e.g. -t IXFR=12345678).

</para>

<para>

The time to wait for a reply can be controlled through the

<option>-W</option> and <option>-w</option> options. The

<option>-W</option> option makes <command>host</command>

wait for

<parameter>wait</parameter> seconds. If <parameter>wait</parameter>

is less than one, the wait interval is set to one second. When the

<option>-w</option> option is used, <command>host</command>

will

effectively wait forever for a reply. The time to wait for a response

will be set to the number of seconds given by the hardware's maximum

value for an integer quantity.

</para>

<para>

The <option>-m</option> can be used to set the memory usage debugging

flags

<parameter>record</parameter>, <parameter>usage</parameter> and

<parameter>trace</parameter>.

</para>

</refsect1>

<refsect1>

<title>FILES</title>

<para><filename>/etc/resolv.conf</filename>

</para>

</refsect1>

<refsect1>

<title>SEE ALSO</title>

<para><citerefentry>

<refentrytitle>dig</refentrytitle><manvolnum>1</manvolnum>

</citerefentry>,

<citerefentry>

<refentrytitle>named</refentrytitle><manvolnum>8</manvolnum>

</citerefentry>.

</para>

</refsect1>

</refentry><!--