Nslookup command

Updated: 11/12/2023 by Computer Hope
nslookup command

Nslookup is an MS-DOS utility that enables users to look up the IP address of a domain or host on a network. The nslookup command can also perform a reverse lookup using an IP address to find the domain or host associated with that IP address.


If you are using earlier versions of Microsoft Windows (Windows 95, Windows 98, or Windows Me) and you need the nslookup command, you must download an alternative, third-party program.


Nslookup is an external command that is available for the following Microsoft operating systems as nslookup.exe.

Nslookup syntax

Windows Vista and later syntax

nslookup [-opt ...] # interactive mode using default server
nslookup [-opt ...] - server # interactive mode using 'server'
nslookup [-opt ...] host # only look up 'host' using default server
nslookup [-opt ...] host server # only look up 'host' using 'server'

Windows XP syntax

Commands: (identifiers are shown in uppercase, [] means optional)

NAME Print info about the host/domain NAME using default server.
NAME1 NAME2 Same as the command listed above, but uses NAME2 as the server.
help or ? Print info on common commands.
set OPTION Set an option.

all Print options, current server, and host.
[no]debug Print debugging information.
[no]d2 Print exhaustive debugging information.
[no]defname Append domain name to each query.
[no]recurse Ask for a recursive answer to a query.
[no]search Use domain search list.
[no]vc Always use a virtual circuit.
domain=NAME Set default domain name to NAME.
srchlist=N1[/N2/.../N6] Set domain to N1 and search list to N1,N2, etc.
root=NAME Set root server to NAME.
retry=X Set the number of retries to X.
timeout=X Set the initial time-out interval to X seconds.
Type=X Set query type (ex. A,ANY,CNAME,MX,NS,PTR,SOA,SRV).
queryType=X Same as type.
class=X Set query class (ex. IN (Internet), ANY).
[no]msxfr Use MS fast zone transfer.
ixfrver=X Current version to use in IXFR transfer request.
server NAME Set default server to NAME, using the current default server.
lserver NAME Set default server to NAME, using the initial server.
finger [USER] Finger the optional NAME at the current default host.
root Set the current default server to the root.
ls [opt] DOMAIN [> FILE] List addresses in DOMAIN (optional: output to FILE).

-a List canonical names and aliases.
-d Lists all records.
-t type List records of the given type (e.g., A,CNAME,MX,NS,PTR etc.).
view FILE Sort an 'ls' output file and view it with pg.
exit Exit the program.

Nslookup examples

This command is used to perform a reverse lookup on an IP address as shown in the example below. The first section specifies the domain name of the requested server. The IP address for that server is displayed in the second section.

Server: ns.computerhope.com
Name: www.computerhope.com

Running nslookup without specifying an IP address or domain name displays your router's server and address. To get out of the > prompt, type exit and press Enter.