Reverse DNS Email Checker

Check an IP's PTR record and forward-confirmed reverse DNS (FCrDNS) — a check many receiving mail servers require before accepting mail.

About this tool

A PTR record maps an IP address back to a hostname — the reverse of a normal DNS lookup. Forward- Confirmed reverse DNS (FCrDNS) goes one step further: the PTR hostname's own A record must resolve back to the exact same IP. Many receiving mail servers require FCrDNS to pass before accepting a connection at all, treating its absence as a strong spam signal, since legitimate mail infrastructure is expected to have this configured correctly.

If this fails for your mail server

PTR records are set by whoever controls the IP address's allocation — typically your hosting provider or ISP, not your domain registrar or DNS provider. Most hosting providers offer a way to set a custom PTR record for IPs they've assigned you; check your hosting control panel or open a support request if it's not self-service.

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