What Is Reverse DNS?

The purpose of DNS is usually used to translate a domain name into an IP address. This act is called preliminary resolution and is performed whenever you visit a website on the Internet. Reverse DNS (or rDNS), as its name suggests, is a method of resolving an IP address back to a domain name.

Use reverse DNS

The reason we use reverse DNS is the same as why we use standard (forward) DNS. It is easier to remember and identify a domain name as a string of numbers. rDNS is less important than forward DNS because forward DNS records are needed to resolve a website. Domains will continue to load without a DNS reverse record.

Email servers commonly use rDNS to block incoming SPAM messages. Many mail servers are set up to automatically reject messages from an IP address that does not have rDNS in place. Although an rDNS record can block spam, it is not a reliable method and is mostly used as an additional layer of protection. It is also important to note that only enabling rDNS can still result in rejected messages for various reasons. In addition, rDNS is also used in analytics and logging to help provide human-readable data, not protocols consisting solely of IP addresses.