HOST(1)                              BIND9                             HOST(1)



NAME
       host - DNS lookup utility

SYNOPSIS
       host [-aCdlnrsTwv] [-c class] [-N ndots] [-R number] [-t type]
            [-W wait] [-m flag] [-4] [-6] {name} [server]

DESCRIPTION
       host 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, host prints a short summary of its command line
       arguments and options.

       name 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 host will by default perform a reverse lookup for that address.
       server is an optional argument which is either the name or IP address
       of the name server that host should query instead of the server or
       servers listed in /etc/resolv.conf.

       The -a (all) option is equivalent to setting the -v option and asking
       host to make a query of type ANY.

       When the -C option is used, host will attempt to display the SOA
       records for zone name 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.

       The -c option instructs to make a DNS query of class class. This can be
       used to lookup Hesiod or Chaosnet class resource records. The default
       class is IN (Internet).

       Verbose output is generated by host when the -d or -v option is used.
       The two options are equivalent. They have been provided for backwards
       compatibility. In previous versions, the -d option switched on
       debugging traces and -v enabled verbose output.

       List mode is selected by the -l option. This makes host perform a zone
       transfer for zone name. Transfer the zone printing out the NS, PTR and
       address records (A/AAAA). If combined with -a all records will be
       printed.

       The -i 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.

       The -N option sets the number of dots that have to be in name for it to
       be considered absolute. The default value is that defined using the
       ndots statement in /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 search or domain
       directive in /etc/resolv.conf.

       The number of UDP retries for a lookup can be changed with the -R
       option.  number indicates how many times host will repeat a query that
       does not get answered. The default number of retries is 1. If number is
       negative or zero, the number of retries will default to 1.

       Non-recursive queries can be made via the -r option. Setting this
       option clears the RD -- recursion desired -- bit in the query which
       host makes. This should mean that the name server receiving the query
       will not attempt to resolve name. The -r option enables host 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.

       By default host uses UDP when making queries. The -T 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.

       The -4 option forces host to only use IPv4 query transport. The -6
       option forces host to only use IPv6 query transport.

       The -t option is used to select the query type.  type can be any
       recognized query type: CNAME, NS, SOA, SIG, KEY, AXFR, etc. When no
       query type is specified, host automatically selects an appropriate
       query type. By default it looks for A, AAAA, and MX records, but if the
       -C option was given, queries will be made for SOA records, and if name
       is a dotted-decimal IPv4 address or colon-delimited IPv6 address, host
       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).

       The time to wait for a reply can be controlled through the -W and -w
       options. The -W option makes host wait for wait seconds. If wait is
       less than one, the wait interval is set to one second. When the -w
       option is used, host 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's maximum value for an integer quantity.

       The -s option tells host not 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.

       The -m can be used to set the memory usage debugging flags record,
       usage and trace.

IDN SUPPORT
       If host has been built with IDN (internationalized domain name)
       support, it can accept and display non-ASCII domain names.  host
       appropriately converts character encoding of domain name before sending
       a request to DNS server or displaying a reply from the server. If you'd
       like to turn off the IDN support for some reason, defines the
       IDN_DISABLE environment variable. The IDN support is disabled if the
       variable is set when host runs.

FILES
       /etc/resolv.conf

SEE ALSO
       dig(1), named(8).

COPYRIGHT
       Copyright (C) 2004, 2005, 2007, 2008 Internet Systems Consortium, Inc.
       ("ISC")
       Copyright (C) 2000-2002 Internet Software Consortium.



BIND9                            Jun 30, 2000                          HOST(1)
