How to use this tool
- Enter a public IPv4 or IPv6 address, such as 8.8.8.8.
- Run the lookup. The tool builds the appropriate in-addr.arpa or ip6.arpa query and requests PTR records.
- Read the returned hostname and TTL. If you need the name's forward addresses, copy it into hostname lookup.
What is reverse DNS?
Forward DNS maps a name to an address. Reverse DNS asks for names associated with an address through PTR records in a separate DNS namespace. IPv4 queries reverse the address's octets under in-addr.arpa; IPv6 queries reverse its hexadecimal digits under ip6.arpa.
The network controlling the reverse zone manages these records. A PTR name can describe infrastructure or a provider's naming convention. It is not a verified device name, the identity of an individual or proof that a website is hosted there.
Why is there no hostname?
Many public addresses have no PTR record. A missing record alone does not establish a fault. Mail-server operators often care about consistent reverse DNS, while an ordinary browsing connection can work without it.
A returned PTR hostname is not guaranteed to resolve back to the same address. To investigate, use hostname lookup and compare its A or AAAA answers for the same address family. An address lookup can provide separate network registration and approximate location information.
Public resolver scope
Private, local and reserved addresses are rejected here. Their useful names may exist only in your router or organisation's internal DNS. A public resolver cannot reliably tell you how an internal network names its devices.
Cloudflare receives the generated reverse-query name, which represents the searched address. The result stays out of the page URL and custom analytics events; it is not a live connection to the searched address.