FAHAQ

Reverse DNS Lookup

Find the PTR hostname for any IP address.

Free online reverse DNS (PTR) lookup for IPv4 and IPv6. Enter an IP to get its hostname, then see whether it is forward-confirmed (FCrDNS) by resolving the hostname back to the same address — the check mail servers use to fight spam.

How to use the Reverse DNS Lookup

  1. 01Enter an IPv4 or IPv6 address.
  2. 02Click Lookup to fetch its PTR records.
  3. 03Check the forward-confirmed (FCrDNS) status.

Frequently asked questions

What is forward-confirmed reverse DNS (FCrDNS)?

It means the PTR hostname for an IP resolves back to that same IP. Mail servers require it to trust a sending server, so it's a key deliverability check.

Why does an IP have no PTR record?

Reverse DNS is optional and set by whoever controls the IP block. Many residential and cloud IPs simply have no PTR record configured.