1 .\" Copyright (C) 2004, 2005, 2007-2009, 2014, 2015 Internet Systems Consortium, Inc. ("ISC")
2 .\" Copyright (C) 2000-2002 Internet Software Consortium.
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27 .TH "HOST" "1" "2009\-01\-20" "ISC" "BIND9"
28 .\" -----------------------------------------------------------------
29 .\" * Define some portability stuff
30 .\" -----------------------------------------------------------------
31 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
32 .\" http://bugs.debian.org/507673
33 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
34 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
37 .\" -----------------------------------------------------------------
38 .\" * set default formatting
39 .\" -----------------------------------------------------------------
40 .\" disable hyphenation
42 .\" disable justification (adjust text to left margin only)
44 .\" -----------------------------------------------------------------
45 .\" * MAIN CONTENT STARTS HERE *
46 .\" -----------------------------------------------------------------
48 host \- DNS lookup utility
51 \fBhost\fR [\fB\-aCdlnrsTwv\fR] [\fB\-c\ \fR\fB\fIclass\fR\fR] [\fB\-N\ \fR\fB\fIndots\fR\fR] [\fB\-R\ \fR\fB\fInumber\fR\fR] [\fB\-t\ \fR\fB\fItype\fR\fR] [\fB\-W\ \fR\fB\fIwait\fR\fR] [\fB\-m\ \fR\fB\fIflag\fR\fR] [\fB\-4\fR] [\fB\-6\fR] [\fB\-v\fR] [\fB\-V\fR] {name} [server]
55 is a simple utility for performing DNS lookups\&. It is normally used to convert names to IP addresses and vice versa\&. When no arguments or options are given,
57 prints a short summary of its command line arguments and options\&.
60 is the domain name that is to be looked up\&. It can also be a dotted\-decimal IPv4 address or a colon\-delimited IPv6 address, in which case
62 will by default perform a reverse lookup for that address\&.
64 is an optional argument which is either the name or IP address of the name server that
66 should query instead of the server or servers listed in
71 (all) option is equivalent to setting the
75 to make a query of type ANY\&.
81 will attempt to display the SOA records for zone
83 from all the listed authoritative name servers for that zone\&. The list of name servers is defined by the NS records that are found for the zone\&.
87 option instructs to make a DNS query of class
88 \fIclass\fR\&. This can be used to lookup Hesiod or Chaosnet class resource records\&. The default class is IN (Internet)\&.
90 Verbose output is generated by
96 option is used\&. The two options are equivalent\&. They have been provided for backwards compatibility\&. In previous versions, the
98 option switched on debugging traces and
100 enabled verbose output\&.
102 List mode is selected by the
106 perform a zone transfer for zone
107 \fIname\fR\&. Transfer the zone printing out the NS, PTR and address records (A/AAAA)\&. If combined with
109 all records will be printed\&.
113 option specifies that reverse lookups of IPv6 addresses should use the IP6\&.INT domain as defined in RFC1886\&. The default is to use IP6\&.ARPA\&.
117 option sets the number of dots that have to be in
119 for it to be considered absolute\&. The default value is that defined using the ndots statement in
120 /etc/resolv\&.conf, or 1 if no ndots statement is present\&. Names with fewer dots are interpreted as relative names and will be searched for in the domains listed in the
125 /etc/resolv\&.conf\&.
127 The number of UDP retries for a lookup can be changed with the
131 indicates how many times
133 will repeat a query that does not get answered\&. The default number of retries is 1\&. If
135 is negative or zero, the number of retries will default to 1\&.
137 Non\-recursive queries can be made via the
139 option\&. Setting this option clears the
141 \(em recursion desired \(em bit in the query which
143 makes\&. This should mean that the name server receiving the query will not attempt to resolve
148 to mimic the behavior 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\&.
152 uses UDP when making queries\&. The
154 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\&.
160 to only use IPv4 query transport\&. The
164 to only use IPv6 query transport\&.
168 option is used to select the query type\&.
170 can be any recognized query type: CNAME, NS, SOA, SIG, KEY, AXFR, etc\&. When no query type is specified,
172 automatically selects an appropriate query type\&. By default, it looks for A, AAAA, and MX records, but if the
174 option was given, queries will be made for SOA records, and if
176 is a dotted\-decimal IPv4 address or colon\-delimited IPv6 address,
178 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)\&.
180 The time to wait for a reply can be controlled through the
192 is less than one, the wait interval is set to one second\&. When the
196 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\*(Aqs maximum value for an integer quantity\&.
202 to send the query to the next nameserver if any server responds with a SERVFAIL response, which is the reverse of normal stub resolver behavior\&.
206 can be used to set the memory usage debugging flags
216 to print the version number and exit\&.
221 has been built with IDN (internationalized domain name) support, it can accept and display non\-ASCII domain names\&.
223 appropriately converts character encoding of domain name before sending a request to DNS server or displaying a reply from the server\&. If you\*(Aqd like to turn off the IDN support for some reason, defines the
225 environment variable\&. The IDN support is disabled if the variable is set when
237 \fBInternet Systems Consortium, Inc\&.\fR
240 Copyright \(co 2004, 2005, 2007-2009, 2014, 2015 Internet Systems Consortium, Inc. ("ISC")
242 Copyright \(co 2000-2002 Internet Software Consortium.