A reverse zone is a zone whose purpose is the mapping of IP addresses to names. Nearly all reverse zones are descended from the IN-ADDR.ARPA zone.

The process of mapping IP addresses to names is useful:

• For use in tracing routes on the internet to identify routers between source and destination. Assigning names on the train stations between point A and point B.
• For Chat and FTP servers it is useful to restrict access to hosts in certain zones.
• To reverse the tide of SPAM, some mail servers will not connect to a mail server whose reverse record is misconfigured.