Reverse DNS – What is it?
Reverse DNS, also known as rDNS, is a DNS lookup that maps an IP address to its domain name. It is absolutely the opposite of Forward DNS lookup, where the domain name links to the IP address where it is hosted.
In the majority of cases, rDNS is an additional service provided by a DNS hosting provider. Once you implement such a service, you should create a Master Reverse zone and add PTR records to it. That way, you are able to provide evidence that your IP address and your domain name have a proper match.
Thanks to the created PTR record, you actually confirm that the IP address is associated with the domain name. As a result, you are minimizing the chance and avoiding fraud. Additionally, you can implement Reverse DNS both with IPv4 address and A record and with IPv6 address and AAAA record.