IP to Hostname (Reverse DNS)
Run a reverse DNS lookup on any public IP address and see the PTR records it resolves to. Free online reverse IP checker.
This check runs from our server, not from your browser, and is rate limited. Nothing you enter is stored. Private and internal addresses are refused on purpose.
What this tool is for
A reverse lookup asks the opposite question: which name claims this address. It matters for mail, where a missing or generic PTR record is one of the reasons messages land in spam, and it is often the fastest way to identify who owns a server hitting your logs. This is one of the few tools here that needs a server, because the question is about the internet rather than about your data. The request is made from our server, rate limited, and nothing you enter is stored.
How to use it
- Enter an IPv4 or IPv6 address.
- Read the PTR records, if the owner published any.
Frequently asked questions
Nothing came back. Is that broken?
No. Reverse records are optional and many addresses have none. Only the owner of the address block can publish them.
Why does mail delivery care about this?
Receiving servers check that a sending IP has a PTR record and that it points back to a matching name. Missing or mismatched records are a common reason legitimate mail is treated as suspicious.