Nslookup
Updated: April 17, 2012
Applies To: Windows Server 2003, Windows Vista, Windows Server 2008, Windows Server 2003 R2, Windows Server 2008 R2, Windows Server 2012, Windows Server 2003 with SP1, Windows 8
Displays information that you can use to diagnose Domain Name System (DNS) infrastructure. Before using this tool, you should be familiar with how DNS works. The Nslookup command-line tool is available only if you have installed the TCP/IP protocol.
Nslookup [<-SubCommand ...>] [{<ComputerToFind> | -<Server>}]
Nslookup /exit
Nslookup /finger [<UserName>] [{[>] <FileName>|[>>] <FileName>}]
Nslookup /{help | ?}
Nslookup /ls [<Option>] <DNSDomain> [{[>] <FileName>|[>>] <FileName>}]
Nslookup /lserver <DNSDomain>
Nslookup /root
Nslookup /server <DNSDomain>
Nslookup /set <KeyWord>[=<Value>]
Nslookup /set all
Nslookup /set class=<Class>
Nslookup /set [no]d2
Nslookup /set [no]debug
Nslookup /set [no]defname
Nslookup /set domain=<DomainName>
Nslookup /set [no]ignore
Nslookup /set port=<Port>
Nslookup /set querytype=<ResourceRecordType>
Nslookup /set [no]recurse
Nslookup /set retry=<Number>
Nslookup /set root=<RootServer>
Nslookup /set [no]search
Nslookup /set srchlist=<DomainName>[/...]
Nslookup /set timeout=<Number>
Nslookup /set type=<ResourceRecordType>
Nslookup /set [no]vc
Nslookup /view <FileName>
Parameter
Description
Exits nslookup.
Connects with the finger server on the current computer.
Displays a short summary of nslookup subcommands.
Lists information for a DNS domain.
Changes the default server to the specified DNS domain.
Changes the default server to the server for the root of the DNS domain name space.
Changes the default server to the specified DNS domain.
Changes configuration settings that affect how lookups function.
Prints the current values of the configuration settings.
Changes the query class. The class specifies the protocol group of the information.
Turns exhaustive Debugging Mode on or off. All fields of every packet are printed.
Turns Debugging Mode on or off.
Appends the default DNS domain name to a single component lookup request. A single component is a component that contains no periods.
Changes the default DNS domain name to the name specified.
Ignores packet truncation errors.
Changes the default TCP/UDP DNS name server port to the value specified.
Changes the resource record type for the query.
Tells the DNS name server to query other servers if it does not have the information.
Sets the number of retries.
Changes the name of the root server used for queries.
Appends the DNS domain names in the DNS domain search list to the request until an answer is received. This applies when the set and the lookup request contain at least one period, but do not end with a trailing period.
Changes the default DNS domain name and search list.
Changes the initial number of seconds to wait for a reply to a request.
Changes the resource record type for the query.
Specifies to use or not use a virtual circuit when sending requests to the server.
Sorts and lists the output of the previous ls subcommand or commands.
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If ComputerToFind is an IP address and the query is for an A or PTR resource record type, the name of the computer is returned. If ComputerToFind is a name and does not have a trailing period, the default DNS domain name is appended to the name. This behavior depends on the state of the following set subcommands: domain, srchlist, defname, and search.
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If you type a hyphen (-) instead of ComputerToFind, the command prompt changes to nslookup interactive mode.
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The command-line length must be less than 256 characters.
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Nslookup has two modes: interactive and noninteractive.
If you need to look up only a single piece of data, use noninteractive mode. For the first parameter, type the name or IP address of the computer that you want to look up. For the second parameter, type the name or IP address of a DNS name server. If you omit the second argument, nslookup uses the default DNS name server.
If you need to look up more than one piece of data, you can use interactive mode. Type a hyphen (-) for the first parameter and the name or IP address of a DNS name server for the second parameter. Or, omit both parameters and nslookup uses the default DNS name server. Following are some tips about working in interactive mode:
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To interrupt interactive commands at any time, press CTRL+B.
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To exit, type exit.
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To treat a built-in command as a computer name, precede it with the escape character (\).
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An unrecognized command is interpreted as a computer name.
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If the lookup request fails, nslookup prints an error message. The following table lists possible error messages.
Error message
Description
Timed out
The server did not respond to a request after a certain amount of time and a certain number of retries. You can set the time-out period with the set timeout subcommand. You can set the number of retries with the set retry subcommand.
No response from server
No DNS name server is running on the server computer.
No records
The DNS name server does not have resource records of the current query type for the computer, although the computer name is valid. The query type is specified with the set querytype command.
Nonexistent domain
The computer or DNS domain name does not exist.
Connection refused
-or-
Network is unreachable
The connection to the DNS name server or finger server could not be made. This error commonly occurs with ls and finger requests.
Server failure
The DNS name server found an internal inconsistency in its database and could not return a valid answer.
Refused
The DNS name server refused to service the request.
Format error
The DNS name server found that the request packet was not in the proper format. It may indicate an error in nslookup.
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For more information about the nslookup command and DNS, see the following resources:
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Lee, T., Davies, J. 2000. Microsoft Windows 2000 TCP/IP Protocols and Services Technical Reference. Redmond, Washington: Microsoft Press.
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Albitz, P., Loukides, M. and C. Liu. 2001. DNS and BIND, Fourth Edition. Sebastopol, California: O’Reilly and Associates, Inc.
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Larson, M. and C. Liu. 2001. DNS on Windows 2000. Sebastopol, California: O’Reilly and Associates, Inc.
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Each command-line option consists of a hyphen (-) followed immediately by the command name and, in some cases, an equal sign (=) and then a value. For example, to change the default query type to host (computer) information and the initial time-out to 10 seconds, type:
nslookup -querytype=hinfo -timeout=10