can use the Name Server Lookup (NSLOOKUP) command to query the Domain
Name Service for information about
domain names and IP addresses. If
you enter a domain name, you get back the IP address to which it corresponds,
and if you enter an IP number, then you get back the domain
name to which it corresponds. In practice, NSLOOKUP reaches out over the Internet
from an authorized name server, and
the information returned for convenient display.
If you first set the type to mx with the command
"set type=mx", then NSLOOKUP also returns all sorts of interesting
about the name server that manages the
domain that you look up. For additional fun, you can lookup the IP addresses
returned by your first NSLOOKUP query and follow the chain of server administration
the NSLOOKUP program by typing
"exit". Resources are provided below for running NSLOOKUP on operating systems
and websites, and references provided for a similar system called Dig.
NSLOOKUP programs. NSLOOKUP was originally written on a Unix system,
and so is easily run on most Linux variants
by simply typing "nslookup" on the command line. On Windows systems
you need to search your computer
for the program "nslookup.exe". On Macintosh, there are two
- In the Terminal application (found at Applications -> Utilities
nslookup is available and used as with any Unix system.
- For a GUI equivalent, use Applications -> Utilities -> Network
Utility, which has a "Lookup" tab in its window. Just enter
the address to look up, or the IP for reverse DNS lookup. (Network Utility
has a lot
of other capabilities
as well since it is basically a wrapper around the functionality of a number
of Unix network-related command-line utilities.)
Online websites. You can also access
NSLOOKUP online from the following websites.
Dig. The Domain Information Groper (Dig)
program provides NSLOOKUP type capabilities
through DNS lookup, as well as special features like "reverse digs" .
Dig installed on a Linux system. The following websites provide online Dig services: