Advantages Of Nslookup

By Technology Last updated Tuesday, May/07/2024

Cross-Platform

The first advantage of nslookup is that it works nearly identically on every computing platform. It's installed as part of the TCP/IP protocol stack, and is integrated into the basic root protocol that drives the Internet. Microsoft's implementation has a few quirks compared to the standard Unix implementation, but the basic format of the command remains the same. Learn how to use nslookup once, and you'll know 90 percent of what it does on any computer on the Internet.

Nslookup on the Unix and Windows platforms has a noninteractive mode. This mode works by entering the command "Nslookup -option hostname server." The part of the command format labeled "-option" is replaced with one of the optional command flags. This is useful when you need to do a quick query of a server and get a short response back.

Nslookup's interactive mode allows for a lot of remote information gathering about a server, and remote diagnostic testing. To start it, type "nslookup -hostname," followed by pressing the "Enter" key. The program will give you an interactive prompt and you can type commands directly and get immediate responses to them. The first two commands most administrators explore are the "debug" and "d2" commands, which give extensive diagnostic reports on the domain server system as seen by your computer.

There are more nslookup options, including changing the default name server port, setting specific query types and several varieties of domain name server search parameters, ranging from limiting your search parameters to specific subsets of the domain name system, the format of the domain name service reports and how many retry options and recursion attempts to use.

Nslookup returns a number of standard diagnostics on points of failure. These include telling you if no name server daemon is running on the specified host, whether the connection has timed out, whether the domain exists at all or if the queried server refuses the connection. Many of the common "Internet errors" reported to ISPs in service outages are nslookup reports sent to the end user or the technical support person.