NsLookup is a network administration and command line tool that is available for most operating systems. It is used to query DNS or Domain Name Systems in order to obtain them or an IP address. These are needed for mapping DNS records.
NsLookup stands for name server look up and use the computers DNS resolver library to operate from. It performs queries and is configured by the operating system’s resolv.conf file, automatically. This utility has since been considered obsolete are many other similar host and dig programs have been invented. Nonetheless, NsLookup is still used by some.
NsLookup has two modes of operation, interactive and non-interactive. When in interactive mode, or programmed without arguments, users issue parameter requests and configurations when prompted to do so. When in non-interactive mode the parameter and query are represented by command line arguments. The syntax for running non-interactive mode is
nslookup [-option] [hostname] [server]
How to Use NsLookup
Type “˜nslookup’ in the command prompt window. The command prompt window is found in Start Menu and then in Accessories.
The program will display the default server information as well as the DNS server address. It will then show the “˜>’ button. Enter the domain name of the IP you would like to check.
For example entering www.cisco.com and pressing enter will show 198.133.219.25 as the DNS server address. Additionally entering www.dlink.com will show 64.7.210.132 as the DNS server address.
I some cases multiple address may share domain names. This usually occurs with popular domains like www.microsoft.com, www.aol.com, and www.yahoo.com.
If you have accidental entered the wrong domain name or if the domain does not exist the program will prompt by saying “˜non-existent domain’.
Some users receive a “˜DNS request timed out’ prompt. This simple means that the domain name which was entered had failed to be resolved at that current moment. The DNS server address may be either invalid or down. Type in other address to try and resolve the problem.
NsLookup also enables users to check an address’s translation by using other DNS server addresses. This can be done with a secondary DNS server. Enter the command “˜server new-DNS-server-IP”� It will check the address translation and change it.
In order to interrupt a interactive command, pressing CTRL and C at the same time is effective.
Typing “˜set all’ will bring up a complete listing of available options.
In order to find dissimilar data types enter “˜set query type’ or “˜set type command’. The initial query for these names will bring about an authoritative answer while all other queries will bring about non-authoritative answers.
At any time throughout this process users can type help into the screen. A list will formulate with all available NsLookup commands. When you are finished type exit and the program will exit interactive mode. For any additional troubleshooting and testing of DNS servers, users can use the Nslookup utility. Following these steps will enable anyone to be able to use NsLookup.