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Reverse DNS lookup

Given an IP address, return the PTR record. Useful when confirming an outbound mail server's rDNS matches its EHLO banner (missing or mismatched PTR is a classic spam-filter trip), tracing who owns a suspicious IP, or validating an auto-assigned PaaS hostname.

Accepts IPv4 and IPv6. Private (RFC 1918), loopback, and link-local ranges are rejected. They only resolve on the local network.

Example result for example.com

Sample data. Run the check above to see yours.

PTR record found

Pass

192.0.2.10 points back to mx1.example.com, and that name resolves to 192.0.2.10 (forward-confirmed).

PTR mx1.example.com
Forward A 192.0.2.10

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