Home/Reverse DNS / PTR Lookup
↩️

Reverse DNS / PTR Lookup

Look up the hostname for an IP address and check Forward-Confirmed rDNS

↩️ Results
↩️
Enter an IP address or domain to perform a reverse DNS lookup

ℹ️ About Reverse DNS and FCrDNS

A PTR record maps an IP address back to a hostname — the reverse of what an A record does. Mail servers use this to verify that a sending IP has a legitimate hostname configured.

Forward-Confirmed Reverse DNS (FCrDNS) is the gold standard for mail server deliverability. It means:

  • The IP has a PTR record pointing to a hostname (e.g. mail.yourdomain.com)
  • That hostname has an A record pointing back to the original IP

Without a matching PTR record, many large mail providers (Gmail, Microsoft, Yahoo) will reject or heavily penalise your outbound mail. Your hosting provider or VPS provider needs to set the PTR record — it's not done in your domain's DNS zone.