Reverse DNS (rDNS)

Reverse DNS (rDNS) is the opposite of the DNS. The DNS is queried for the IP address of a certain hostname. In reverse DNS, the hostname is returned for a certain IP address.

images/webmaster/reverse-dns-rdns.jpg

Reverse DNS uses a pointer record (PTR) to match an IP address with a domain or subdomain. PTR records are generally set with a hosting provider or server level.