What is a PTR record?

A Pointer (PTR) record maps an IP address to its corresponding domain hostname, facilitating reverse routing diagnostics. It acts as the exact inverse of standard forward mapping 'A' records.

Why is my IP resolving to generic ISP domains?

ISPs automatically provision default PTR records (e.g. '123-45-67-89.isp.net') to all IP blocks they control. Dedicated domain hostnames must be manually set by the network administrative owner.

IP to Hostname

Resolve IPv4 or IPv6 addresses back to their authoritative Pointer (PTR) hostnames using reverse DNS routing.

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Frequently Asked Questions

Receiving email servers perform reverse DNS lookups on connecting mail exchange IPs to verify they match the sending domain name. If the PTR lookup fails or mismatch occurs, emails are marked as spam.

IPv6 reverse zones use the '.ip6.arpa' suffix. The full 128-bit IPv6 address is expanded to its complete 32 hex nibbles, separated with dots in completely reversed order (e.g. '1.1.1.1.0.0.0.0...ip6.arpa').

IP to Hostname

Frequently Asked Questions

Why is reverse DNS important for email delivery?

How is an IPv6 reverse name constructed?