Reverse DNS delegations

in-addr.arpa

The reverse tree for IPv4 addresses. The name derives from 'inverse (IP) address' and 'ARPA', one of the organisations behind the creation of the Internet.

ip6.arpa

The equivalent reverse tree for IPv6 delegations.

ip6.int

This reverse tree for IPv6 addresses is deprecated.

If you hold IPv6 addresses with an existing ip6.int reverse domain objects, then you create ip6.arpa reverse domain objects. As of 1 June, 2006, ip6.int domain objects are no longer maintained.