DNS & Domain
Open Reverse DNS →Reverse lookup starts with an address
Reverse DNS asks for names associated with an IP address through PTR records. It is separate from looking up a hostname’s A or AAAA records. Enter a public IPv4 or IPv6 address in Reverse DNS. A returned name can identify a network’s naming convention, but it is not proof of legal ownership or the identity of the person using the connection.
Check a PTR name in both directions
After obtaining a PTR hostname, use DNS Lookup to query its address records. Check whether the original IP is among the returned addresses, using A for IPv4 or AAAA for IPv6. Matching forward and reverse records can be useful operational evidence, especially for mail systems. A mismatch can indicate stale records or a deliberate hosting arrangement; investigate rather than automatically declaring abuse.
Know who can change the record
Reverse zones follow address allocation and delegation. The operator providing the public IP usually controls the PTR setting or delegates it to the customer. Adding a PTR-like record to an ordinary forward DNS zone does not necessarily change public reverse lookup results. If you rent a server, check its provider’s reverse-DNS setting and confirm the hostname already resolves to the intended address.
Use it as one email-delivery check
For outbound email, inspect the IP that actually sends the message. It may differ from the website address or even the inbound MX service. Compare the PTR name, forward answers and configured SMTP identity with the mail provider’s requirements. Also review authentication and reputation separately. A matching PTR does not guarantee inbox placement, and a missing record does not mean every service on that IP is down.
Worked example
Illustrative example — not a live test IP: 192.0.2.25 PTR: mail.example.com A for mail.example.com: 192.0.2.25 These documentation values illustrate a matching pair.
What to check next
- Find the actual public address involved in the connection.
- Look up its PTR name, then resolve that name forward.
- Request PTR changes from the operator responsible for the IP.
Common questions
Can one IP have more than one PTR name?
DNS can return multiple PTR records. Treat each as published data and verify the name relevant to your service.
Does reverse DNS identify a user?
No. It describes published address-to-name information, often associated with a provider or server.