What does reverse lookup mean for "white" IP = localhost?

Question

Domain Name System

Do you often see IP addresses for which reverse lookup = localhost?
For example,
113.188.9.154
117.0.175.3
123.28.107.173
220.231.127.12

Answer 1

The DNS for these addresses is not configured correctly.

Answer 2

Either DNS is set up this way on purpose, such as white addresses for internal use, don't bother.
But in any case, all questions to the administrator of the corresponding DNS zone.