Networking / Beginners

Using the nslookup Command

The nslookup command is a powerful tool for diagnosing DNS problems. You know you're experiencing a DNS problem when you can access a resource by specifying its IP address but not its DNS name. For example, if you can get to by typing in your browser's address bar but not by typing, you have a DNS problem.

Looking up an IP address

The simplest use of nslookup is to look up the IP address for a given DNS name. For example, how did I know that was the IP address for I used nslookup to find out:

Non-authoritative answer:

As you can see, just type nslookup followed by the DNS name you want to look up. Nslookup issues a DNS query to find out. This DNS query was sent to the server named at It then displayed the IP address that's associated with namely,

Tip: In some cases, you may find that using an nslookup command gives you the wrong IP address for a host name. To know that for sure, of course, you have to know with certainty what the host IP address should be. For example, if you know that your server is but Nslookup returns a completely different IP address for your server when you query the server's host name, something is probably wrong with one of the DNS records.

Using nslookup subcommands

If you use nslookup without any arguments, the nslookup command enters a subcommand mode. It displays a prompt character (>) to let you know that you're in nslookup subcommand mode rather than at a normal Windows command prompt. In subcommand mode, you can enter various subcommands to set options or to perform queries. You can type a question mark (?) to get a list of these commands. Table-2 lists the subcommands you'll use most.

The Most Commonly Used nslookup Subcommands
SubcommandWhat It Does
nameQueries the current name server for the specified name.
server nameSets the current name server to the server you specify.
rootSets the root server as the current server.
set type=xSpecifies the type of records to be displayed, such as A, CNAME, MX, NS, PTR, or SOA. Specify ANY to display all records.
set debugTurns on Debug mode, which displays detailed information about each query.
set nodebugTurns off Debug mode.
set recurseEnables recursive searches.
set norecurseDisables recursive searches.
exitExits the nslookup program and returns you to a command prompt.
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