Find the hostname associated with any IP address
Reverse DNS lookup (rDNS) resolves an IP address back to a hostname using PTR records. It is the opposite of a standard DNS lookup which resolves hostnames to IPs.
Reverse DNS is used for email server verification, security logging, network troubleshooting, and identifying who owns an IP address. Many mail servers reject emails from IPs without proper rDNS.
A PTR (Pointer) record maps an IP address to a domain name. It is stored in a special reverse DNS zone and is the foundation of reverse DNS lookups.