Definition - What does NsLookup mean?
NsLookup is a tool included in many operating systems that can look up IP addresses and perform other searches on DNS domains and servers. This resource is housed in a utility called nslookup.exe. NsLookup is a basic way to get fundamental DNS information quickly and easily.
Techopedia explains NsLookup
NsLookup is typically a command-line tool, which means that it uses the command-line structure familiar to many users who have used older PC-DOS operating systems. In order to use command-line tools, users may have to shell out of a Windows-based environment in order to access the command-line interface.
In addition to looking up server information, NsLookup can be used to test IP connections. Users can set items like retry and timeout, designate a root server, or get debugging information. NsLookup can also be used to check mail exchanger or MX records that designate routing for emails according to what servers are attached to a particular domain. A full list of possible commands is available in NsLookup with the command "?" or "help."