For IPv4 addresses (A records) reverse mappings are stored in a separate set of subdomains called the IN-ADDR.ARPA hierarchy. An IP address is turned into the corresponding IN-ADDR.ARPA name by reversing the order of the octets and appending .IN-ADDR.ARPA.

For A6 records reverse mappings are stored in the zone defined by prefix name. Reverse zone is derived from the prefix name by adding IP6 label in front of prefix name.

For AAAA records reverse mappings are stored under ip6.arpa zones.

For example, the reverse mapping of the IP address 192.168.1.2 is stored under the name 2.1.168.192.IN-ADDR.ARPA. That name should have a PTR record which points at the domain name of the machine with the IP address 192.168.1.2. For IPv6 address N.X.COM. A6 64 ::1234:5678:9ABC:DEF0 PREFIX.X.COM reverse map PTR record name is \[x123456789ABCDEF0].IP6.PREFIX.X.COM.

If more than one domain name points at the same IP address, the corresponding IN-ADDR.ARPA name may have several PTR records.

When you add or remove hosts in your forward zones, NameSurfer will automatically try to add or remove a PTR record for the corresponding reverse map name. This automatic updating only works when the corresponding reverse map domain in question is maintained in the same NameSurfer server as the forward zone. If this is not the case, a PTR record should be added or removed manually.

You can choose not to create the reverse map automatically by unchecking the checkbox controlling automatic reverse map creation.