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It can also be a dotted-decimal IPv4 address or a colon-delimited 64 IPv6 address, in which case <span><strong class="command">host</strong></span> will by 65 default 66 perform a reverse lookup for that address. 67 <em class="parameter"><code>server</code></em> is an optional argument which 68 is either 69 the name or IP address of the name server that <span><strong class="command">host</strong></span> 70 should query instead of the server or servers listed in 71 <code class="filename">/etc/resolv.conf</code>. 72 </p> 73<p> 74 The <code class="option">-a</code> (all) option is equivalent to setting the 75 <code class="option">-v</code> option and asking <span><strong class="command">host</strong></span> to make 76 a query of type ANY. 77 </p> 78<p> 79 When the <code class="option">-C</code> option is used, <span><strong class="command">host</strong></span> 80 will attempt to display the SOA records for zone 81 <em class="parameter"><code>name</code></em> from all the listed 82 authoritative name 83 servers for that zone. The list of name servers is defined by the NS 84 records that are found for the zone. 85 </p> 86<p> 87 The <code class="option">-c</code> option instructs to make a DNS query of class 88 <em class="parameter"><code>class</code></em>. This can be used to lookup 89 Hesiod or 90 Chaosnet class resource records. The default class is IN (Internet). 91 </p> 92<p> 93 Verbose output is generated by <span><strong class="command">host</strong></span> when 94 the 95 <code class="option">-d</code> or <code class="option">-v</code> option is used. The two 96 options are equivalent. They have been provided for backwards 97 compatibility. In previous versions, the <code class="option">-d</code> option 98 switched on debugging traces and <code class="option">-v</code> enabled verbose 99 output. 100 </p> 101<p> 102 List mode is selected by the <code class="option">-l</code> option. This makes 103 <span><strong class="command">host</strong></span> perform a zone transfer for zone 104 <em class="parameter"><code>name</code></em>. Transfer the zone printing out 105 the NS, PTR 106 and address records (A/AAAA). If combined with <code class="option">-a</code> 107 all records will be printed. 108 </p> 109<p> 110 The <code class="option">-i</code> 111 option specifies that reverse lookups of IPv6 addresses should 112 use the IP6.INT domain as defined in RFC1886. 113 The default is to use IP6.ARPA. 114 </p> 115<p> 116 The <code class="option">-N</code> option sets the number of dots that have to be 117 in <em class="parameter"><code>name</code></em> for it to be considered 118 absolute. The 119 default value is that defined using the ndots statement in 120 <code class="filename">/etc/resolv.conf</code>, or 1 if no ndots 121 statement is 122 present. Names with fewer dots are interpreted as relative names and 123 will be searched for in the domains listed in the <span class="type">search</span> 124 or <span class="type">domain</span> directive in 125 <code class="filename">/etc/resolv.conf</code>. 126 </p> 127<p> 128 The number of UDP retries for a lookup can be changed with the 129 <code class="option">-R</code> option. <em class="parameter"><code>number</code></em> 130 indicates 131 how many times <span><strong class="command">host</strong></span> will repeat a query 132 that does 133 not get answered. The default number of retries is 1. If 134 <em class="parameter"><code>number</code></em> is negative or zero, the 135 number of 136 retries will default to 1. 137 </p> 138<p> 139 Non-recursive queries can be made via the <code class="option">-r</code> option. 140 Setting this option clears the <span class="type">RD</span> — recursion 141 desired — bit in the query which <span><strong class="command">host</strong></span> makes. 142 This should mean that the name server receiving the query will not 143 attempt to resolve <em class="parameter"><code>name</code></em>. The 144 <code class="option">-r</code> option enables <span><strong class="command">host</strong></span> 145 to mimic 146 the behavior of a name server by making non-recursive queries and 147 expecting to receive answers to those queries that are usually 148 referrals to other name servers. 149 </p> 150<p> 151 By default, <span><strong class="command">host</strong></span> uses UDP when making 152 queries. The 153 <code class="option">-T</code> option makes it use a TCP connection when querying 154 the name server. TCP will be automatically selected for queries that 155 require it, such as zone transfer (AXFR) requests. 156 </p> 157<p> 158 The <code class="option">-4</code> option forces <span><strong class="command">host</strong></span> to only 159 use IPv4 query transport. The <code class="option">-6</code> option forces 160 <span><strong class="command">host</strong></span> to only use IPv6 query transport. 161 </p> 162<p> 163 The <code class="option">-t</code> option is used to select the query type. 164 <em class="parameter"><code>type</code></em> can be any recognized query 165 type: CNAME, 166 NS, SOA, SIG, KEY, AXFR, etc. When no query type is specified, 167 <span><strong class="command">host</strong></span> automatically selects an appropriate 168 query 169 type. By default, it looks for A, AAAA, and MX records, but if the 170 <code class="option">-C</code> option was given, queries will be made for SOA 171 records, and if <em class="parameter"><code>name</code></em> is a 172 dotted-decimal IPv4 173 address or colon-delimited IPv6 address, <span><strong class="command">host</strong></span> will 174 query for PTR records. If a query type of IXFR is chosen the starting 175 serial number can be specified by appending an equal followed by the 176 starting serial number (e.g. -t IXFR=12345678). 177 </p> 178<p> 179 The time to wait for a reply can be controlled through the 180 <code class="option">-W</code> and <code class="option">-w</code> options. The 181 <code class="option">-W</code> option makes <span><strong class="command">host</strong></span> 182 wait for 183 <em class="parameter"><code>wait</code></em> seconds. If <em class="parameter"><code>wait</code></em> 184 is less than one, the wait interval is set to one second. When the 185 <code class="option">-w</code> option is used, <span><strong class="command">host</strong></span> 186 will 187 effectively wait forever for a reply. The time to wait for a response 188 will be set to the number of seconds given by the hardware's maximum 189 value for an integer quantity. 190 </p> 191<p> 192 The <code class="option">-s</code> option tells <span><strong class="command">host</strong></span> 193 <span class="emphasis"><em>not</em></span> to send the query to the next nameserver 194 if any server responds with a SERVFAIL response, which is the 195 reverse of normal stub resolver behavior. 196 </p> 197<p> 198 The <code class="option">-m</code> can be used to set the memory usage debugging 199 flags 200 <em class="parameter"><code>record</code></em>, <em class="parameter"><code>usage</code></em> and 201 <em class="parameter"><code>trace</code></em>. 202 </p> 203<p> 204 The <code class="option">-V</code> option causes <span><strong class="command">host</strong></span> 205 to print the version number and exit. 206 </p> 207</div> 208<div class="refsect1" lang="en"> 209<a name="id2614966"></a><h2>IDN SUPPORT</h2> 210<p> 211 If <span><strong class="command">host</strong></span> has been built with IDN (internationalized 212 domain name) support, it can accept and display non-ASCII domain names. 213 <span><strong class="command">host</strong></span> appropriately converts character encoding of 214 domain name before sending a request to DNS server or displaying a 215 reply from the server. 216 If you'd like to turn off the IDN support for some reason, defines 217 the <code class="envar">IDN_DISABLE</code> environment variable. 218 The IDN support is disabled if the variable is set when 219 <span><strong class="command">host</strong></span> runs. 220 </p> 221</div> 222<div class="refsect1" lang="en"> 223<a name="id2614995"></a><h2>FILES</h2> 224<p><code class="filename">/etc/resolv.conf</code> 225 </p> 226</div> 227<div class="refsect1" lang="en"> 228<a name="id2615009"></a><h2>SEE ALSO</h2> 229<p><span class="citerefentry"><span class="refentrytitle">dig</span>(1)</span>, 230 <span class="citerefentry"><span class="refentrytitle">named</span>(8)</span>. 231 </p> 232</div> 233</div> 234<div class="navfooter"> 235<hr> 236<table width="100%" summary="Navigation footer"> 237<tr> 238<td width="40%" align="left"> 239<a accesskey="p" href="man.dig.html">Prev</a>�</td> 240<td width="20%" align="center"><a accesskey="u" href="Bv9ARM.ch13.html">Up</a></td> 241<td width="40%" align="right">�<a accesskey="n" href="man.delv.html">Next</a> 242</td> 243</tr> 244<tr> 245<td width="40%" align="left" valign="top">dig�</td> 246<td width="20%" align="center"><a accesskey="h" href="Bv9ARM.html">Home</a></td> 247<td width="40%" align="right" valign="top">�delv</td> 248</tr> 249</table> 250</div> 251<p style="text-align: center;">BIND 9.10.2-P4</p> 252</body> 253</html> 254