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+.. Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+..
+.. SPDX-License-Identifier: MPL-2.0
+..
+.. This Source Code Form is subject to the terms of the Mozilla Public
+.. License, v. 2.0. If a copy of the MPL was not distributed with this
+.. file, you can obtain one at https://mozilla.org/MPL/2.0/.
+..
+.. See the COPYRIGHT file distributed with this work for additional
+.. information regarding copyright ownership.
+
+.. highlight: console
+
+.. _man_host:
+
+host - DNS lookup utility
+-------------------------
+
+Synopsis
+~~~~~~~~
+
+:program:`host` [**-aACdlnrsTUwv**] [**-c** class] [**-N** ndots] [**-p** port] [**-R** number] [**-t** type] [**-W** wait] [**-m** flag] [ [**-4**] | [**-6**] ] [**-v**] [**-V**] {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`` by default performs 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``.
+
+Options
+~~~~~~~
+
+``-4``
+ This option specifies that only IPv4 should be used for query transport. See also the ``-6`` option.
+
+``-6``
+ This option specifies that only IPv6 should be used for query transport. See also the ``-4`` option.
+
+``-a``
+ The ``-a`` ("all") option is normally equivalent to ``-v -t ANY``. It
+ also affects the behavior of the ``-l`` list zone option.
+
+``-A``
+ The ``-A`` ("almost all") option is equivalent to ``-a``, except that RRSIG,
+ NSEC, and NSEC3 records are omitted from the output.
+
+``-c class``
+ This option specifies the query class, which can be used to lookup HS (Hesiod) or CH (Chaosnet)
+ class resource records. The default class is IN (Internet).
+
+``-C``
+ This option indicates that ``named`` should check consistency, meaning that ``host`` queries 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.
+
+``-d``
+ This option prints debugging traces, and is equivalent to the ``-v`` verbose option.
+
+``-l``
+ This option tells ``named`` to list the zone, meaning the ``host`` command performs a zone transfer of zone
+ ``name`` and prints out the NS, PTR, and address records (A/AAAA).
+
+ Together, the ``-l -a`` options print all records in the zone.
+
+``-N ndots``
+ This option specifies the number of dots (``ndots``) 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 are searched for in the domains listed in the ``search`` or
+ ``domain`` directive in ``/etc/resolv.conf``.
+
+``-p port``
+ This option specifies the port to query on the server. The default is 53.
+
+``-r``
+ This option specifies a non-recursive query; setting this option clears the RD (recursion
+ desired) bit in the query. This means that the name server
+ receiving the query does 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 can be referrals to other name servers.
+
+``-R number``
+ This option specifies the number of retries for UDP queries. If ``number`` is negative or zero,
+ the number of retries is silently set to 1. The default value is 1, or
+ the value of the ``attempts`` option in ``/etc/resolv.conf``, if set.
+
+``-s``
+ This option tells ``named`` *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.
+
+``-t type``
+ This option specifies the query type. The ``type`` argument can be any recognized query type:
+ CNAME, NS, SOA, TXT, DNSKEY, 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. If the ``-C`` option is given, queries are made for SOA
+ records. If ``name`` is a dotted-decimal IPv4 address or
+ colon-delimited IPv6 address, ``host`` queries for PTR records.
+
+ If a query type of IXFR is chosen, the starting serial number can be
+ specified by appending an equals sign (=), followed by the starting serial
+ number, e.g., ``-t IXFR=12345678``.
+
+``-T``; ``-U``
+ This option specifies TCP or UDP. By default, ``host`` uses UDP when making queries; the
+ ``-T`` option makes it use a TCP connection when querying the name
+ server. TCP is automatically selected for queries that require
+ it, such as zone transfer (AXFR) requests. Type ``ANY`` queries default
+ to TCP, but can be forced to use UDP initially via ``-U``.
+
+``-m flag``
+ This option sets memory usage debugging: the flag can be ``record``, ``usage``, or
+ ``trace``. The ``-m`` option can be specified more than once to set
+ multiple flags.
+
+``-v``
+ This option sets verbose output, and is equivalent to the ``-d`` debug option. Verbose output
+ can also be enabled by setting the ``debug`` option in
+ ``/etc/resolv.conf``.
+
+``-V``
+ This option prints the version number and exits.
+
+``-w``
+ This option sets "wait forever": the query timeout is set to the maximum possible. See
+ also the ``-W`` option.
+
+``-W wait``
+ This options sets the length of the wait timeout, indicating that ``named`` should wait for up to ``wait`` seconds for a reply. If ``wait`` is
+ less than 1, the wait interval is set to 1 second.
+
+ By default, ``host`` waits for 5 seconds for UDP responses and 10
+ seconds for TCP connections. These defaults can be overridden by the
+ ``timeout`` option in ``/etc/resolv.conf``.
+
+ See also the ``-w`` option.
+
+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 a domain name before sending
+a request to a DNS server or displaying a reply from the server.
+To turn off IDN support, define the ``IDN_DISABLE``
+environment variable. IDN support is disabled if the variable is set
+when ``host`` runs.
+
+Files
+~~~~~
+
+``/etc/resolv.conf``
+
+See Also
+~~~~~~~~
+
+:manpage:`dig(1)`, :manpage:`named(8)`.