208 lines
6.6 KiB
ReStructuredText
208 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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.. iscman:: nslookup
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.. program:: nslookup
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.. _man_nslookup:
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nslookup - query Internet name servers interactively
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----------------------------------------------------
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Synopsis
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~~~~~~~~
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:program:`nslookup` [-option] [name | -] [server]
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Description
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~~~~~~~~~~~
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:program:`nslookup` is a program to query Internet domain name servers.
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:program:`nslookup` has two modes: interactive and non-interactive. Interactive
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mode allows the user to query name servers for information about various
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hosts and domains or to print a list of hosts in a domain.
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Non-interactive mode prints just the name and requested
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information for a host or domain.
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Arguments
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~~~~~~~~~
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Interactive mode is entered in the following cases:
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a. when no arguments are given (the default name server is used);
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b. when the first argument is a hyphen (-) and the second argument is
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the host name or Internet address of a name server.
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Non-interactive mode is used when the name or Internet address of the
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host to be looked up is given as the first argument. The optional second
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argument specifies the host name or address of a name server.
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Options can also be specified on the command line if they precede the
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arguments and are prefixed with a hyphen. For example, to change the
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default query type to host information, with an initial timeout of 10
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seconds, type:
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::
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nslookup -query=hinfo -timeout=10
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The ``-version`` option causes :program:`nslookup` to print the version number
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and immediately exit.
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Interactive Commands
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~~~~~~~~~~~~~~~~~~~~
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``host [server]``
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This command looks up information for :iscman:`host` using the current default server or
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using ``server``, if specified. If :iscman:`host` is an Internet address and the
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query type is A or PTR, the name of the host is returned. If :iscman:`host` is
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a name and does not have a trailing period (``.``), the search list is used
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to qualify the name.
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To look up a host not in the current domain, append a period to the
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name.
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``server domain`` | ``lserver domain``
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These commands change the default server to ``domain``; ``lserver`` uses the initial
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server to look up information about ``domain``, while ``server`` uses the
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current default server. If an authoritative answer cannot be found,
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the names of servers that might have the answer are returned.
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``root``
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This command is not implemented.
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``finger``
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This command is not implemented.
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``ls``
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This command is not implemented.
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``view``
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This command is not implemented.
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``help``
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This command is not implemented.
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``?``
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This command is not implemented.
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``exit``
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This command exits the program.
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``set keyword[=value]``
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This command is used to change state information that affects the
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lookups. Valid keywords are:
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``all``
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This keyword prints the current values of the frequently used options to
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``set``. Information about the current default server and host is
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also printed.
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``class=value``
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This keyword changes the query class to one of:
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``IN``
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the Internet class
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``CH``
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the Chaos class
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``HS``
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the Hesiod class
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``ANY``
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wildcard
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The class specifies the protocol group of the information. The default
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is ``IN``; the abbreviation for this keyword is ``cl``.
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``nodebug``
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This keyword turns on or off the display of the full response packet, and any
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intermediate response packets, when searching. The default for this keyword is
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``nodebug``; the abbreviation for this keyword is ``[no]deb``.
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``nod2``
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This keyword turns debugging mode on or off. This displays more about what
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nslookup is doing. The default is ``nod2``.
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``domain=name``
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This keyword sets the search list to ``name``.
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``nosearch``
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If the lookup request contains at least one period, but does not end
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with a trailing period, this keyword appends the domain names in the domain
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search list to the request until an answer is received. The default is ``search``.
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``port=value``
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This keyword changes the default TCP/UDP name server port to ``value`` from
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its default, port 53. The abbreviation for this keyword is ``po``.
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``querytype=value`` | ``type=value``
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This keyword changes the type of the information query to ``value``. The
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defaults are A and then AAAA; the abbreviations for these keywords are
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``q`` and ``ty``.
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Please note that it is only possible to specify one query type. Only the default
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behavior looks up both when an alternative is not specified.
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``norecurse``
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This keyword tells the name server to query other servers if it does not have
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the information. The default is ``recurse``; the abbreviation for this
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keyword is ``[no]rec``.
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``ndots=number``
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This keyword sets the number of dots (label separators) in a domain that
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disables searching. Absolute names always stop searching.
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``retry=number``
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This keyword sets the number of retries to ``number``.
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``timeout=number``
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This keyword changes the initial timeout interval to wait for a reply to
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``number``, in seconds.
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``novc``
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This keyword indicates that a virtual circuit should always be used when sending requests to the server.
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``novc`` is the default.
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``nofail``
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This keyword tries the next nameserver if a nameserver responds with SERVFAIL or
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a referral (nofail), or terminates the query (fail) on such a response. The
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default is ``nofail``.
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Return Values
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~~~~~~~~~~~~~
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:program:`nslookup` returns with an exit status of 1 if any query failed, and 0
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otherwise.
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IDN Support
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~~~~~~~~~~~
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If :program:`nslookup` has been built with IDN (internationalized domain name)
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support, it can accept and display non-ASCII domain names. :program:`nslookup`
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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 :program:`nslookup` runs, or when the standard output is not a tty.
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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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:iscman:`dig(1) <dig>`, :iscman:`host(1) <host>`, :iscman:`named(8) <named>`.
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