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This commit converts the license handling to adhere to the REUSE specification. It specifically: 1. Adds used licnses to LICENSES/ directory 2. Add "isc" template for adding the copyright boilerplate 3. Changes all source files to include copyright and SPDX license header, this includes all the C sources, documentation, zone files, configuration files. There are notes in the doc/dev/copyrights file on how to add correct headers to the new files. 4. Handle the rest that can't be modified via .reuse/dep5 file. The binary (or otherwise unmodifiable) files could have license places next to them in <foo>.license file, but this would lead to cluttered repository and most of the files handled in the .reuse/dep5 file are system test files.
172 lines
6.6 KiB
ReStructuredText
172 lines
6.6 KiB
ReStructuredText
.. Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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..
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.. SPDX-License-Identifier: MPL-2.0
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..
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.. This Source Code Form is subject to the terms of the Mozilla Public
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.. License, v. 2.0. If a copy of the MPL was not distributed with this
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.. file, you can obtain one at https://mozilla.org/MPL/2.0/.
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..
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.. See the COPYRIGHT file distributed with this work for additional
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.. information regarding copyright ownership.
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.. highlight: console
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.. _man_host:
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host - DNS lookup utility
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-------------------------
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Synopsis
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~~~~~~~~
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:program:`host` [**-aACdlnrsTUwv**] [**-c** class] [**-N** ndots] [**-p** port] [**-R** number] [**-t** type] [**-W** wait] [**-m** flag] [ [**-4**] | [**-6**] ] [**-v**] [**-V**] {name} [server]
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Description
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~~~~~~~~~~~
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``host`` is a simple utility for performing DNS lookups. It is normally
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used to convert names to IP addresses and vice versa. When no arguments
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or options are given, ``host`` prints a short summary of its
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command-line arguments and options.
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``name`` is the domain name that is to be looked up. It can also be a
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dotted-decimal IPv4 address or a colon-delimited IPv6 address, in which
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case ``host`` by default performs a reverse lookup for that address.
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``server`` is an optional argument which is either the name or IP
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address of the name server that ``host`` should query instead of the
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server or servers listed in ``/etc/resolv.conf``.
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Options
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~~~~~~~
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``-4``
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This option specifies that only IPv4 should be used for query transport. See also the ``-6`` option.
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``-6``
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This option specifies that only IPv6 should be used for query transport. See also the ``-4`` option.
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``-a``
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The ``-a`` ("all") option is normally equivalent to ``-v -t ANY``. It
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also affects the behavior of the ``-l`` list zone option.
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``-A``
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The ``-A`` ("almost all") option is equivalent to ``-a``, except that RRSIG,
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NSEC, and NSEC3 records are omitted from the output.
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``-c class``
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This option specifies the query class, which can be used to lookup HS (Hesiod) or CH (Chaosnet)
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class resource records. The default class is IN (Internet).
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``-C``
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This option indicates that ``named`` should check consistency, meaning that ``host`` queries the SOA records for zone
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``name`` from all the listed authoritative name servers for that
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zone. The list of name servers is defined by the NS records that are
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found for the zone.
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``-d``
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This option prints debugging traces, and is equivalent to the ``-v`` verbose option.
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``-l``
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This option tells ``named` to list the zone, meaning the ``host`` command performs a zone transfer of zone
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``name`` and prints out the NS, PTR, and address records (A/AAAA).
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Together, the ``-l -a`` options print all records in the zone.
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``-N ndots``
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This option specifies the number of dots (``ndots``) that have to be in ``name`` for it to be
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considered absolute. The default value is that defined using the
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``ndots`` statement in ``/etc/resolv.conf``, or 1 if no ``ndots`` statement
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is present. Names with fewer dots are interpreted as relative names,
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and are searched for in the domains listed in the ``search`` or
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``domain`` directive in ``/etc/resolv.conf``.
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``-p port``
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This option specifies the port to query on the server. The default is 53.
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``-r``
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This option specifies a non-recursive query; setting this option clears the RD (recursion
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desired) bit in the query. This means that the name server
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receiving the query does not attempt to resolve ``name``. The ``-r``
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option enables ``host`` to mimic the behavior of a name server by
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making non-recursive queries, and expecting to receive answers to
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those queries that can be referrals to other name servers.
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``-R number``
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This option specifies the number of retries for UDP queries. If ``number`` is negative or zero,
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the number of retries is silently set to 1. The default value is 1, or
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the value of the ``attempts`` option in ``/etc/resolv.conf``, if set.
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``-s``
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This option tells ``named`` *not* to send the query to the next nameserver if any server responds
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with a SERVFAIL response, which is the reverse of normal stub
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resolver behavior.
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``-t type``
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This option specifies the query type. The ``type`` argument can be any recognized query type:
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CNAME, NS, SOA, TXT, DNSKEY, AXFR, etc.
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When no query type is specified, ``host`` automatically selects an
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appropriate query type. By default, it looks for A, AAAA, and MX
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records. If the ``-C`` option is given, queries are made for SOA
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records. If ``name`` is a dotted-decimal IPv4 address or
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colon-delimited IPv6 address, ``host`` queries for PTR records.
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If a query type of IXFR is chosen, the starting serial number can be
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specified by appending an equals sign (=), followed by the starting serial
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number, e.g., ``-t IXFR=12345678``.
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``-T``; ``-U``
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This option specifies TCP or UDP. By default, ``host`` uses UDP when making queries; the
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``-T`` option makes it use a TCP connection when querying the name
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server. TCP is automatically selected for queries that require
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it, such as zone transfer (AXFR) requests. Type ``ANY`` queries default
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to TCP, but can be forced to use UDP initially via ``-U``.
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``-m flag``
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This option sets memory usage debugging: the flag can be ``record``, ``usage``, or
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``trace``. The ``-m`` option can be specified more than once to set
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multiple flags.
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``-v``
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This option sets verbose output, and is equivalent to the ``-d`` debug option. Verbose output
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can also be enabled by setting the ``debug`` option in
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``/etc/resolv.conf``.
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``-V``
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This option prints the version number and exits.
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``-w``
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This option sets "wait forever": the query timeout is set to the maximum possible. See
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also the ``-W`` option.
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``-W wait``
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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
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less than 1, the wait interval is set to 1 second.
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By default, ``host`` waits for 5 seconds for UDP responses and 10
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seconds for TCP connections. These defaults can be overridden by the
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``timeout`` option in ``/etc/resolv.conf``.
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See also the ``-w`` option.
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IDN Support
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~~~~~~~~~~~
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If ``host`` has been built with IDN (internationalized domain name)
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support, it can accept and display non-ASCII domain names. ``host``
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appropriately converts character encoding of a domain name before sending
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a request to a DNS server or displaying a reply from the server.
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To turn off IDN support, define the ``IDN_DISABLE``
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environment variable. IDN support is disabled if the variable is set
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when ``host`` runs.
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Files
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~~~~~
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``/etc/resolv.conf``
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See Also
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~~~~~~~~
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:manpage:`dig(1)`, :manpage:`named(8)`.
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