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