2 - Copyright (C) 2004-2015 Internet Systems Consortium, Inc. ("ISC")
3 - Copyright (C) 2000-2003 Internet Software Consortium.
5 - Permission to use, copy, modify, and/or distribute this software for any
6 - purpose with or without fee is hereby granted, provided that the above
7 - copyright notice and this permission notice appear in all copies.
9 - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 - PERFORMANCE OF THIS SOFTWARE.
19 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
21 <meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
22 <link rel="home" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual">
23 <link rel="up" href="Bv9ARM.ch13.html" title="Manual pages">
24 <link rel="prev" href="man.dig.html" title="dig">
25 <link rel="next" href="man.dnssec-checkds.html" title="dnssec-checkds">
27 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
28 <div class="navheader">
29 <table width="100%" summary="Navigation header">
30 <tr><th colspan="3" align="center">host</th></tr>
32 <td width="20%" align="left">
33 <a accesskey="p" href="man.dig.html">Prev</a> </td>
34 <th width="60%" align="center">Manual pages</th>
35 <td width="20%" align="right"> <a accesskey="n" href="man.dnssec-checkds.html">Next</a>
41 <div class="refentry">
42 <a name="man.host"></a><div class="titlepage"></div>
43 <div class="refnamediv">
45 <p>host — DNS lookup utility</p>
47 <div class="refsynopsisdiv">
49 <div class="cmdsynopsis"><p><code class="command">host</code> [<code class="option">-aCdlnrsTwv</code>] [<code class="option">-c <em class="replaceable"><code>class</code></em></code>] [<code class="option">-N <em class="replaceable"><code>ndots</code></em></code>] [<code class="option">-R <em class="replaceable"><code>number</code></em></code>] [<code class="option">-t <em class="replaceable"><code>type</code></em></code>] [<code class="option">-W <em class="replaceable"><code>wait</code></em></code>] [<code class="option">-m <em class="replaceable"><code>flag</code></em></code>] [<code class="option">-4</code>] [<code class="option">-6</code>] [<code class="option">-v</code>] [<code class="option">-V</code>] {name} [server]</p></div>
51 <div class="refsection">
52 <a name="id-1.14.3.7"></a><h2>DESCRIPTION</h2>
53 <p><span class="command"><strong>host</strong></span>
54 is a simple utility for performing DNS lookups.
55 It is normally used to convert names to IP addresses and vice versa.
56 When no arguments or options are given,
57 <span class="command"><strong>host</strong></span>
58 prints a short summary of its command line arguments and options.
60 <p><em class="parameter"><code>name</code></em> is the domain name that is to be
62 up. It can also be a dotted-decimal IPv4 address or a colon-delimited
63 IPv6 address, in which case <span class="command"><strong>host</strong></span> will by
65 perform a reverse lookup for that address.
66 <em class="parameter"><code>server</code></em> is an optional argument which
68 the name or IP address of the name server that <span class="command"><strong>host</strong></span>
69 should query instead of the server or servers listed in
70 <code class="filename">/etc/resolv.conf</code>.
73 The <code class="option">-a</code> (all) option is equivalent to setting the
74 <code class="option">-v</code> option and asking <span class="command"><strong>host</strong></span> to make
78 When the <code class="option">-C</code> option is used, <span class="command"><strong>host</strong></span>
79 will attempt to display the SOA records for zone
80 <em class="parameter"><code>name</code></em> from all the listed
82 servers for that zone. The list of name servers is defined by the NS
83 records that are found for the zone.
86 The <code class="option">-c</code> option instructs to make a DNS query of class
87 <em class="parameter"><code>class</code></em>. This can be used to lookup
89 Chaosnet class resource records. The default class is IN (Internet).
92 Verbose output is generated by <span class="command"><strong>host</strong></span> when
94 <code class="option">-d</code> or <code class="option">-v</code> option is used. The two
95 options are equivalent. They have been provided for backwards
96 compatibility. In previous versions, the <code class="option">-d</code> option
97 switched on debugging traces and <code class="option">-v</code> enabled verbose
101 List mode is selected by the <code class="option">-l</code> option. This makes
102 <span class="command"><strong>host</strong></span> perform a zone transfer for zone
103 <em class="parameter"><code>name</code></em>. Transfer the zone printing out
105 and address records (A/AAAA). If combined with <code class="option">-a</code>
106 all records will be printed.
109 The <code class="option">-i</code>
110 option specifies that reverse lookups of IPv6 addresses should
111 use the IP6.INT domain as defined in RFC1886.
112 The default is to use IP6.ARPA.
115 The <code class="option">-N</code> option sets the number of dots that have to be
116 in <em class="parameter"><code>name</code></em> for it to be considered
118 default value is that defined using the ndots statement in
119 <code class="filename">/etc/resolv.conf</code>, or 1 if no ndots
121 present. Names with fewer dots are interpreted as relative names and
122 will be searched for in the domains listed in the <span class="type">search</span>
123 or <span class="type">domain</span> directive in
124 <code class="filename">/etc/resolv.conf</code>.
127 The number of UDP retries for a lookup can be changed with the
128 <code class="option">-R</code> option. <em class="parameter"><code>number</code></em>
130 how many times <span class="command"><strong>host</strong></span> will repeat a query
132 not get answered. The default number of retries is 1. If
133 <em class="parameter"><code>number</code></em> is negative or zero, the
135 retries will default to 1.
138 Non-recursive queries can be made via the <code class="option">-r</code> option.
139 Setting this option clears the <span class="type">RD</span> — recursion
140 desired — bit in the query which <span class="command"><strong>host</strong></span> makes.
141 This should mean that the name server receiving the query will not
142 attempt to resolve <em class="parameter"><code>name</code></em>. The
143 <code class="option">-r</code> option enables <span class="command"><strong>host</strong></span>
145 the behavior of a name server by making non-recursive queries and
146 expecting to receive answers to those queries that are usually
147 referrals to other name servers.
150 By default, <span class="command"><strong>host</strong></span> uses UDP when making
152 <code class="option">-T</code> option makes it use a TCP connection when querying
153 the name server. TCP will be automatically selected for queries that
154 require it, such as zone transfer (AXFR) requests.
157 The <code class="option">-4</code> option forces <span class="command"><strong>host</strong></span> to only
158 use IPv4 query transport. The <code class="option">-6</code> option forces
159 <span class="command"><strong>host</strong></span> to only use IPv6 query transport.
162 The <code class="option">-t</code> option is used to select the query type.
163 <em class="parameter"><code>type</code></em> can be any recognized query
165 NS, SOA, SIG, KEY, AXFR, etc. When no query type is specified,
166 <span class="command"><strong>host</strong></span> automatically selects an appropriate
168 type. By default, it looks for A, AAAA, and MX records, but if the
169 <code class="option">-C</code> option was given, queries will be made for SOA
170 records, and if <em class="parameter"><code>name</code></em> is a
172 address or colon-delimited IPv6 address, <span class="command"><strong>host</strong></span> will
173 query for PTR records. If a query type of IXFR is chosen the starting
174 serial number can be specified by appending an equal followed by the
175 starting serial number (e.g. -t IXFR=12345678).
178 The time to wait for a reply can be controlled through the
179 <code class="option">-W</code> and <code class="option">-w</code> options. The
180 <code class="option">-W</code> option makes <span class="command"><strong>host</strong></span>
182 <em class="parameter"><code>wait</code></em> seconds. If <em class="parameter"><code>wait</code></em>
183 is less than one, the wait interval is set to one second. When the
184 <code class="option">-w</code> option is used, <span class="command"><strong>host</strong></span>
186 effectively wait forever for a reply. The time to wait for a response
187 will be set to the number of seconds given by the hardware's maximum
188 value for an integer quantity.
191 The <code class="option">-s</code> option tells <span class="command"><strong>host</strong></span>
192 <span class="emphasis"><em>not</em></span> to send the query to the next nameserver
193 if any server responds with a SERVFAIL response, which is the
194 reverse of normal stub resolver behavior.
197 The <code class="option">-m</code> can be used to set the memory usage debugging
199 <em class="parameter"><code>record</code></em>, <em class="parameter"><code>usage</code></em> and
200 <em class="parameter"><code>trace</code></em>.
203 The <code class="option">-V</code> option causes <span class="command"><strong>host</strong></span>
204 to print the version number and exit.
207 <div class="refsection">
208 <a name="id-1.14.3.8"></a><h2>IDN SUPPORT</h2>
210 If <span class="command"><strong>host</strong></span> has been built with IDN (internationalized
211 domain name) support, it can accept and display non-ASCII domain names.
212 <span class="command"><strong>host</strong></span> appropriately converts character encoding of
213 domain name before sending a request to DNS server or displaying a
214 reply from the server.
215 If you'd like to turn off the IDN support for some reason, defines
216 the <code class="envar">IDN_DISABLE</code> environment variable.
217 The IDN support is disabled if the variable is set when
218 <span class="command"><strong>host</strong></span> runs.
221 <div class="refsection">
222 <a name="id-1.14.3.9"></a><h2>FILES</h2>
223 <p><code class="filename">/etc/resolv.conf</code>
226 <div class="refsection">
227 <a name="id-1.14.3.10"></a><h2>SEE ALSO</h2>
228 <p><span class="citerefentry"><span class="refentrytitle">dig</span>(1)</span>,
229 <span class="citerefentry"><span class="refentrytitle">named</span>(8)</span>.
233 <div class="navfooter">
235 <table width="100%" summary="Navigation footer">
237 <td width="40%" align="left">
238 <a accesskey="p" href="man.dig.html">Prev</a> </td>
239 <td width="20%" align="center"><a accesskey="u" href="Bv9ARM.ch13.html">Up</a></td>
240 <td width="40%" align="right"> <a accesskey="n" href="man.dnssec-checkds.html">Next</a>
244 <td width="40%" align="left" valign="top">dig </td>
245 <td width="20%" align="center"><a accesskey="h" href="Bv9ARM.html">Home</a></td>
246 <td width="40%" align="right" valign="top"> <span class="application">dnssec-checkds</span>
251 <p xmlns:db="http://docbook.org/ns/docbook" style="text-align: center;">BIND 9.9.9-P4 (Extended Support Version)</p>