nslookup.rst revision 1.1.1.4
1.. Copyright (C) Internet Systems Consortium, Inc. ("ISC") 2.. 3.. SPDX-License-Identifier: MPL-2.0 4.. 5.. This Source Code Form is subject to the terms of the Mozilla Public 6.. License, v. 2.0. If a copy of the MPL was not distributed with this 7.. file, you can obtain one at https://mozilla.org/MPL/2.0/. 8.. 9.. See the COPYRIGHT file distributed with this work for additional 10.. information regarding copyright ownership. 11 12.. highlight: console 13 14.. iscman:: nslookup 15.. program:: nslookup 16.. _man_nslookup: 17 18nslookup - query Internet name servers interactively 19---------------------------------------------------- 20 21Synopsis 22~~~~~~~~ 23 24:program:`nslookup` [-option] [name | -] [server] 25 26Description 27~~~~~~~~~~~ 28 29:program:`nslookup` is a program to query Internet domain name servers. 30:program:`nslookup` has two modes: interactive and non-interactive. Interactive 31mode allows the user to query name servers for information about various 32hosts and domains or to print a list of hosts in a domain. 33Non-interactive mode prints just the name and requested 34information for a host or domain. 35 36Arguments 37~~~~~~~~~ 38 39Interactive mode is entered in the following cases: 40 41a. when no arguments are given (the default name server is used); 42 43b. when the first argument is a hyphen (-) and the second argument is 44 the host name or Internet address of a name server. 45 46Non-interactive mode is used when the name or Internet address of the 47host to be looked up is given as the first argument. The optional second 48argument specifies the host name or address of a name server. 49 50Options can also be specified on the command line if they precede the 51arguments and are prefixed with a hyphen. For example, to change the 52default query type to host information, with an initial timeout of 10 53seconds, type: 54 55:: 56 57 nslookup -query=hinfo -timeout=10 58 59The ``-version`` option causes :program:`nslookup` to print the version number 60and immediately exit. 61 62Interactive Commands 63~~~~~~~~~~~~~~~~~~~~ 64 65``host [server]`` 66 This command looks up information for :iscman:`host` using the current default server or 67 using ``server``, if specified. If :iscman:`host` is an Internet address and the 68 query type is A or PTR, the name of the host is returned. If :iscman:`host` is 69 a name and does not have a trailing period (``.``), the search list is used 70 to qualify the name. 71 72 To look up a host not in the current domain, append a period to the 73 name. 74 75``server domain`` | ``lserver domain`` 76 These commands change the default server to ``domain``; ``lserver`` uses the initial 77 server to look up information about ``domain``, while ``server`` uses the 78 current default server. If an authoritative answer cannot be found, 79 the names of servers that might have the answer are returned. 80 81``root`` 82 This command is not implemented. 83 84``finger`` 85 This command is not implemented. 86 87``ls`` 88 This command is not implemented. 89 90``view`` 91 This command is not implemented. 92 93``help`` 94 This command is not implemented. 95 96``?`` 97 This command is not implemented. 98 99``exit`` 100 This command exits the program. 101 102``set keyword[=value]`` 103 This command is used to change state information that affects the 104 lookups. Valid keywords are: 105 106 ``all`` 107 This keyword prints the current values of the frequently used options to 108 ``set``. Information about the current default server and host is 109 also printed. 110 111 ``class=value`` 112 This keyword changes the query class to one of: 113 114 ``IN`` 115 the Internet class 116 117 ``CH`` 118 the Chaos class 119 120 ``HS`` 121 the Hesiod class 122 123 ``ANY`` 124 wildcard 125 126 The class specifies the protocol group of the information. The default 127 is ``IN``; the abbreviation for this keyword is ``cl``. 128 129 ``nodebug`` 130 This keyword turns on or off the display of the full response packet, and any 131 intermediate response packets, when searching. The default for this keyword is 132 ``nodebug``; the abbreviation for this keyword is ``[no]deb``. 133 134 ``nod2`` 135 This keyword turns debugging mode on or off. This displays more about what 136 nslookup is doing. The default is ``nod2``. 137 138 ``domain=name`` 139 This keyword sets the search list to ``name``. 140 141 ``nosearch`` 142 If the lookup request contains at least one period, but does not end 143 with a trailing period, this keyword appends the domain names in the domain 144 search list to the request until an answer is received. The default is ``search``. 145 146 ``port=value`` 147 This keyword changes the default TCP/UDP name server port to ``value`` from 148 its default, port 53. The abbreviation for this keyword is ``po``. 149 150 ``querytype=value`` | ``type=value`` 151 This keyword changes the type of the information query to ``value``. The 152 defaults are A and then AAAA; the abbreviations for these keywords are 153 ``q`` and ``ty``. 154 155 Please note that it is only possible to specify one query type. Only the default 156 behavior looks up both when an alternative is not specified. 157 158 ``norecurse`` 159 This keyword tells the name server to query other servers if it does not have 160 the information. The default is ``recurse``; the abbreviation for this 161 keyword is ``[no]rec``. 162 163 ``ndots=number`` 164 This keyword sets the number of dots (label separators) in a domain that 165 disables searching. Absolute names always stop searching. 166 167 ``retry=number`` 168 This keyword sets the number of retries to ``number``. 169 170 ``timeout=number`` 171 This keyword changes the initial timeout interval to wait for a reply to 172 ``number``, in seconds. 173 174 ``novc`` 175 This keyword indicates that a virtual circuit should always be used when sending requests to the server. 176 ``novc`` is the default. 177 178 ``nofail`` 179 This keyword tries the next nameserver if a nameserver responds with SERVFAIL or 180 a referral (nofail), or terminates the query (fail) on such a response. The 181 default is ``nofail``. 182 183Return Values 184~~~~~~~~~~~~~ 185 186:program:`nslookup` returns with an exit status of 1 if any query failed, and 0 187otherwise. 188 189IDN Support 190~~~~~~~~~~~ 191 192If :program:`nslookup` has been built with IDN (internationalized domain name) 193support, it can accept and display non-ASCII domain names. :program:`nslookup` 194appropriately converts character encoding of a domain name before sending 195a request to a DNS server or displaying a reply from the server. 196To turn off IDN support, define the ``IDN_DISABLE`` 197environment variable. IDN support is disabled if the variable is set 198when :program:`nslookup` runs, or when the standard output is not a tty. 199 200Files 201~~~~~ 202 203``/etc/resolv.conf`` 204 205See Also 206~~~~~~~~ 207 208:iscman:`dig(1) <dig>`, :iscman:`host(1) <host>`, :iscman:`named(8) <named>`. 209