Reverse DNS Lookup Tool
Perform a reverse DNS lookup
Reverse resolution starts with an IPv4 or IPv6 address and looks for its PTR record. This name is configured by the owner of the address block, commonly the hosting or connectivity provider.
Forward-confirming the PTR
The tool can then resolve the returned hostname and check whether it points back to the original address. This FCrDNS check is useful for diagnosing some mail servers, but it does not prove the service’s identity or legitimacy by itself.
Missing or inconsistent results
An address may publish no PTR at all. PTR and A or AAAA records may also be managed separately, explaining temporary or persistent inconsistencies.
Practical notes
Reverse DNS looks up an IP address PTR and can check whether that hostname resolves back to the original address. This consistency is useful but is not proof of identity.
InputsIPv4 and IPv6
CheckForward-confirmed PTR
ResultControlled by IP owner
Frequently asked questions
Who configures a PTR?
The owner or provider of the IP block, not necessarily the domain-name holder.
Can an IP have no PTR?
Yes. Reverse DNS is optional, although recommended for some services, especially mail servers.
Why does the hostname not resolve back to the same IP?
PTR and A/AAAA records may be managed separately or be out of sync.