Reverse DNS

A reverse DNS (Domain Name System) lookup is a process that converts an IP address into a domain name. It is the opposite of a regular DNS lookup, which converts a domain name into an IP address.

Reverse DNS lookups are used to determine the domain name associated with a particular IP address. They are often used by servers and other network devices to identify the hostname of a device that is trying to connect to them. For example, when you try to access a website, the web server may perform a reverse DNS lookup on your IP address to determine the domain name of your device and use it to identify and authenticate you.

Reverse DNS lookups are also used in email systems to verify the identity of senders and help prevent spam and other forms of email abuse.

Reverse DNS lookups are performed using the PTR (pointer) record in the DNS database. The PTR record maps an IP address to a domain name, and it is used to perform reverse DNS lookups.