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Reverse DNS Zone Name

The PTR name to ask for, including the prefixes that have no zone of their own.

One address for a single PTR name, or a prefix to see which zone holds it.

Reverse DNS for 192.0.2.0

Delegating it anyway (RFC 2317)

A prefix inside the last octet has no zone, but RFC 2317 describes a way to delegate one anyway: a zone whose label carries the prefix, and one CNAME per address in the parent zone pointing into it. It looks strange and it is in the specification.

The zone to delegate 0/26.2.0.192.in-addr.arpa
The parent zone, which keeps 64 CNAME records 2.0.192.in-addr.arpa

For example

0.2.0.192.in-addr.arpa  IN CNAME  0.0/26.2.0.192.in-addr.arpa
1.2.0.192.in-addr.arpa  IN CNAME  1.0/26.2.0.192.in-addr.arpa
2.2.0.192.in-addr.arpa  IN CNAME  2.0/26.2.0.192.in-addr.arpa

Nothing here is looked up. This is what to ask for; whether the record exists is a different question, and the DNS lookup tool answers that one. The case worth the page is a prefix that is not on a delegation boundary: a /58 has no ip6.arpa name at all, and the answer is the four zones that cover it rather than a label somebody made up.