Check an IP Address's Reverse DNS
Reverse DNS starts with an IP address and asks for the hostname associated with it in DNS. The answer comes from a PTR record. This is the opposite direction from an A or AAAA lookup, which starts with a name and returns an address. Reverse DNS Lookup performs that reverse query and then checks the returned hostname's address records to see whether they include the original IP.
This comparison is useful when reviewing a server's DNS configuration or investigating a hostname shown in connection logs. The results keep the PTR answer and the forward check together, so a returned name is not mistaken for a confirmed match. A hostname can exist in reverse DNS even when its own address records no longer lead back to the address you entered.
Look Up an Address or a Domain
Enter a complete IPv4 address, an IPv6 address, or a domain name. A domain must be entered without https://, a path, or a port number. When you enter a domain, the lookup first requests its A and AAAA records, then checks the resulting addresses individually. The result may contain several address groups rather than one PTR answer for the entire domain.
- Enter the address or bare domain name and run the lookup.
- Find the address group you want to examine.
- Read each PTR hostname and its forward lookup status.
- Copy the result if you need to compare it with your DNS configuration or share it with the responsible network operator.
Domain input is a convenient starting point, but it does not make the domain and every returned PTR name interchangeable. A domain may point to an address whose reverse name belongs to the hosting network. Review the address beside each name before deciding whether it is relevant to the server you are checking.
Interpret the Forward Check
The forward check asks whether a PTR hostname resolves back to the original address through an A or AAAA record. It compares addresses rather than requiring the hostname to look like the domain you entered. The three outcomes have different meanings:
- Matches means the forward answer includes the original IP address.
- Does not match means the check completed without finding that address in the hostname's relevant address records.
- Could not check means a technical problem prevented a reliable comparison.
For example, suppose an address has a PTR name of edge.example.net. If that name's address records include the starting IP, the forward check matches. If they point somewhere else, the PTR name can still be displayed, but the comparison does not match. A lookup failure is reported separately rather than being presented as a negative DNS answer.
Read TTL and Incomplete Results
Each returned PTR name has a TTL value in seconds. This is the caching lifetime supplied with that DNS answer, not the age of the server or the time since someone changed the record. Cached answers can remain visible while a DNS update is taking effect.
No PTR records found means the completed reverse query supplied no PTR answer for that address. A technical error means the query could not be completed. For domain input, one address family or one reverse query may fail while other results remain available. Read those notices alongside the successful groups instead of treating the whole lookup as complete.
Public DNS and What a Match Confirms
The lookup uses public DNS, including when you enter a private or otherwise nonpublic address. It cannot consult a company's internal DNS servers or read names configured only on your local network. A matching result confirms consistency between the DNS answers obtained here; it does not prove ownership, establish that a service is reachable, or certify that an address is safe.
