How to Network a Reverse Lookup

DNS (Domain Name System) service is a hierarchical database that resolves IP addresses to human-friendly host names that are meaningful, hence easier to remember. DNS supports several types of queries including reverse lookup, in which the DNS service responds with the friendly host names associated with a host's IP address. Finding the host names associated with an email "spam" IP address, so that the host names can be entered in a "spam" filter, is a common reverse lookup application. Perform a reverse lookup when you have the IP address of a network host, and need to find all the host names or "aliases" that represent the host.

• 1

  Select the "Start" button, click "Programs," and then select "Accessories."

• 2

  Right-click on the command line icon and click "Run as Administrator" in the menu that appears.

• 3

  Type "nslookup x.x.x.x" but replace the "x.x.x.x" with the IP address of the host for which you are performing a reverse lookup. Press the "Enter" key. Note the DNS names displayed in the output and verify that they are the DNS addresses that should refer to the IP address entered on the command line.