host.html revision fb84f9014321c5f33c4682de5661b579fcde318f
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - Copyright (C) 2000, 2001 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.
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson - WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>. The argument is provided for
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssoncompatibility with older implemementations. This option is equivalent
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonto making a query of type AXFR.</P
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonoption specifies that reverse lookups of IPv6 addresses should
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonuse the IP6.INT domain and "nibble" labels as defined in RFC1886.
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonThe default is to use IP6.ARPA and binary labels as defined in RFC2874.</P
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"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafssonquery for PTR records.</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
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fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="FILENAME"
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fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="CITEREFENTRY"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REFENTRYTITLE"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas Gustafsson>resolver</SPAN
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="CITEREFENTRY"
fb84f9014321c5f33c4682de5661b579fcde318fAndreas GustafssonCLASS="REFENTRYTITLE"