host.html revision 9016767f4e15191b7c763b8a4ad36a57dc2705a2
9016767f4e15191b7c763b8a4ad36a57dc2705a2Mark Andrews - Copyright (C) 2004 Internet Systems Consortium, Inc. ("ISC")
9016767f4e15191b7c763b8a4ad36a57dc2705a2Mark Andrews - Copyright (C) 2000-2002 Internet Software Consortium.
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - Permission to use, copy, modify, and distribute this software for any
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - purpose with or without fee is hereby granted, provided that the above
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - copyright notice and this permission notice appear in all copies.
9016767f4e15191b7c763b8a4ad36a57dc2705a2Mark Andrews - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
9016767f4e15191b7c763b8a4ad36a57dc2705a2Mark Andrews - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
9016767f4e15191b7c763b8a4ad36a57dc2705a2Mark Andrews - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
9016767f4e15191b7c763b8a4ad36a57dc2705a2Mark Andrews - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
9016767f4e15191b7c763b8a4ad36a57dc2705a2Mark Andrews - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
9016767f4e15191b7c763b8a4ad36a57dc2705a2Mark Andrews - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
9016767f4e15191b7c763b8a4ad36a57dc2705a2Mark Andrews - PERFORMANCE OF THIS SOFTWARE.
9016767f4e15191b7c763b8a4ad36a57dc2705a2Mark Andrews<!-- $Id: host.html,v 1.6 2004/03/05 05:54:24 marka Exp $ -->
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonNAME="GENERATOR"
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fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>host -- DNS lookup utility</DIV
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REFSYNOPSISDIV"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>-aCdlnrTwv</TT
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REPLACEABLE"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REPLACEABLE"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REPLACEABLE"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REPLACEABLE"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REPLACEABLE"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>] {name} [server]</P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REFSECT1"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>DESCRIPTION</H2
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonis a simple utility for performing DNS lookups.
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonIt is normally used to convert names to IP addresses and vice versa.
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonWhen no arguments or options are given,
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonprints a short summary of its command line arguments and options.</P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> is the domain name that is to be looked
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonup. It can also be a dotted-decimal IPv4 address or a colon-delimited
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonIPv6 address, in which case <B
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> will by default
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonperform a reverse lookup for that address.
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> is an optional argument which is either
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonthe name or IP address of the name server that <B
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonshould query instead of the server or servers listed in
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="FILENAME"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> (all) option is equivalent to setting the
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option and asking <B
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssona query of type ANY.</P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option is used, <B
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonwill attempt to display the SOA records for zone
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> from all the listed authoritative name
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonservers for that zone. The list of name servers is defined by the NS
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonrecords that are found for the zone.</P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option instructs to make a DNS query of class
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>. This can be used to lookup Hesiod or
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonChaosnet class resource records. The default class is IN (Internet).</P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>Verbose output is generated by <B
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option is used. The two
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonoptions are equivalent. They have been provided for backwards
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssoncompatibility. In previous versions, the <TT
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonswitched on debugging traces and <TT
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> enabled verbose
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>List mode is selected by the <TT
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option. This makes
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> perform a zone transfer for zone
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
0f44724dbc0fd65c5e1677b70d0f690105291553Mark Andrews>. Transfer the zone printing out the NS, PTR
0f44724dbc0fd65c5e1677b70d0f690105291553Mark Andrewsand address records (A/AAAA). If combined with <TT
0f44724dbc0fd65c5e1677b70d0f690105291553Mark AndrewsCLASS="OPTION"
0f44724dbc0fd65c5e1677b70d0f690105291553Mark Andrewsall records will be printed. </P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonoption specifies that reverse lookups of IPv6 addresses should
0f44724dbc0fd65c5e1677b70d0f690105291553Mark Andrewsuse the IP6.INT domain as defined in RFC1886.
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option sets the number of dots that have to be
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> for it to be considered absolute. The
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssondefault value is that defined using the ndots statement in
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="FILENAME"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>, or 1 if no ndots statement is
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonpresent. Names with fewer dots are interpreted as relative names and
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonwill be searched for in the domains listed in the <SPAN
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="FILENAME"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>The number of UDP retries for a lookup can be changed with the
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonhow many times <B
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> will repeat a query that does
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonnot get answered. The default number of retries is 1. If
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> is negative or zero, the number of
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonretries will default to 1.</P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>Non-recursive queries can be made via the <TT
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonSetting this option clears the <SPAN
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> — recursion
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssondesired — bit in the query which <B
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonThis should mean that the name server receiving the query will not
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonattempt to resolve <TT
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option enables <B
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonthe behaviour of a name server by making non-recursive queries and
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonexpecting to receive answers to those queries that are usually
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonreferrals to other name servers.</P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> uses UDP when making queries. The
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option makes it use a TCP connection when querying
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonthe name server. TCP will be automatically selected for queries that
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonrequire it, such as zone transfer (AXFR) requests.</P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option is used to select the query type.
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> can be any recognised query type: CNAME,
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonNS, SOA, SIG, KEY, AXFR, etc. When no query type is specified,
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> automatically selects an appropriate query
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssontype. By default it looks for A records, but if the
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option was given, queries will be made for SOA
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonrecords, and if <TT
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> is a dotted-decimal IPv4
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonaddress or colon-delimited IPv6 address, <B
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
0f44724dbc0fd65c5e1677b70d0f690105291553Mark Andrewsquery for PTR records. If a query type of IXFR is chosen the starting
0f44724dbc0fd65c5e1677b70d0f690105291553Mark Andrewsserial number can be specified by appending an equal followed by the
0f44724dbc0fd65c5e1677b70d0f690105291553Mark Andrewsstarting serial number (e.g. -t IXFR=12345678).</P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>The time to wait for a reply can be controlled through the
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option makes <B
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> seconds. If <TT
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="PARAMETER"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonis less than one, the wait interval is set to one second. When the
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson> option is used, <B
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="COMMAND"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssoneffectively wait forever for a reply. The time to wait for a response
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonwill be set to the number of seconds given by the hardware's maximum
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonvalue for an integer quantity.</P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REFSECT1"
0f44724dbc0fd65c5e1677b70d0f690105291553Mark AndrewsNAME="AEN106"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="FILENAME"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REFSECT1"
0f44724dbc0fd65c5e1677b70d0f690105291553Mark AndrewsNAME="AEN110"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="CITEREFENTRY"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REFENTRYTITLE"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="CITEREFENTRY"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REFENTRYTITLE"