Reverse DNS asks for a hostname associated with an IP address. For IPv4, reverse the four address parts and add in-addr.arpa. The documentation address 203.0.113.7 therefore produces the query name shown below. This is a syntax example, not a claim that this address has a live PTR record.
Example input
203.0.113.7Expected result
7.113.0.203.in-addr.arpa.Try it step by step
- Read the IPv4 address from right to left: 7, 113, 0, 203.
- Join those parts with dots and append in-addr.arpa. to form the reverse query name.
- Open the connection checker to request reverse DNS for your actual connection. Read its status together with any returned hostname.
How to read the result
A PTR response is a hostname published by the administrator of the reverse DNS zone. A missing record, timeout or unavailable resolver can leave the hostname empty while the connection still works. IPv6 uses a different reverse form under ip6.arpa and is not represented by this IPv4 example.
Limits and important details
PTR does not reveal which DNS servers your device uses. A hostname is not proof of identity, reputation or location. The checker does not invent a hostname when reverse DNS returns no result.