NSLookup Usage Explained in Terms You Can Understand

Trying to learn what NSlookup means can be difficult as most websites tend to use very technical terms and definitions. However, the following information should clear things up a bit. Before you learn how to use NSlookup, understanding what it is is necessary.


NSlookup is a network uti8ly application that is used to get data about Internet servers. Its main function is to locate name server data by making DNS queries.

How to Use

Almost all operating systems have a command line application called nslookup.exe. There are also networks that provide the application or a similar service on the web and do server lookups.

If you are running Windows, you need to start a command prompt and then load the program with this command:

C:\> nslookup

Default Server: resolver1.opendns.com



What this does is check what DNS is set up on the computer.

Nslookup.exe. will respond with the primary IP address linked to the specified domain name. Suppose you want to know the primary address of xyz.com, it would look something like this:

\> xyz.com

Address: (numbers here)

Mail Server Lookup

If you are looking for mail server information on a specific domain, nslookup will use a DNS’ “MX record” feature. There are also some websites that offer support for both primary and backup servers, but not all do. If you want to do a mail server query, the command line is:

\> set type=mx

\> xyz.com

xyz.com MX preference = 100, mail exchanger = xyz.com.mail9.psmtp.com

xyz.com MX preference = 200, mail exchanger = xyz.com.mail10.psmtp.com

xyz.com MX preference = 300, mail exchanger = xyz.com.mail11.psmtp.com

xyz.com MX preference = 400, mail exchanger = xyz.com.mail12.psmtp.com

Other Types of Nslookup Queries

This program can also query other seldom used DNS records like SOA, PTR and CNAME and SOA. If you type a question mark at the prompt it will allow the application to print the program’s help file.

More about Using Nslookup.exe in Windows

Before you use the command in Windows, keep in mind that it is an administrative tool designed for testing and resolving problems with DNS servers. There is no need for any manual installation because it is installed with the TCP/IP protocol. Before you can use the utility, you need the TCP/IP protocol to be installed and working. You must then specify a minimum of one DNS server. If not, the IPCONFIG /ALL command won’t run.

Also remember that the utility will devolve based on the current context name. If a name is not fully qualified for the query, it will be appended to the present context. Note: if you are implementing the search list at the Domain Suffix Search Order, devolution will not take place. If you don’t want to use the search list, always utilize a Fully Qualified Domain Name.

The utility can be used in the following modes: noninteractive and interactive. Noninteractive mode can only be used if a single data has to be returned. To use noninteractive use this syntax:

Nslookup [-option] [hostname] [server]

If you want to run interactive mode go to a command prompt and type:

C:\> nslookup

Default Server: nameserver1.domain.com



As long as you know what syntax to use, learning how to use NSlookup won’t be too hard. Although you probably won’t use the command often , it helps to know what they are in case there is a problem with the DNS server.

Jerry is a free lancer writer of http://www.everydayguide.com/ and currently he is understanding the basics of networking like nslookup, ping, loopback address and many more concepts.