Reverse IP Lookup
Look up the reverse DNS (PTR) record for an IP or hostname.
âšī¸ This performs a reverse DNS (PTR) lookup, which returns the single hostname an IP's owner has associated with it - it does not list every domain hosted on that server (that requires a paid data provider, which isn't feasible to run for free).
How Reverse IP Lookup works
How does this tool work?
The input is resolved to a public IP address (private and reserved ranges are rejected), then PHP's gethostbyaddr() runs a DNS PTR lookup against it - essentially asking what hostname the IP's owner has published for that address.
When would I use this?
Handy for checking the reverse DNS a mail server presents, since many receiving mail systems require a matching PTR record to avoid being flagged as spam, or for a general sanity check on a VPS or server's DNS setup.
Why doesn't it list every domain hosted on that IP?
PTR lookups only ever return the single hostname the IP owner configured - not every domain sharing that server. A true 'what domains live on this IP' report needs a paid third-party dataset that crawls and indexes hosting at scale, which a free tool like this can't provide; if the owner never set a PTR record (common on shared hosting or budget VPS plans), you'll see "No PTR record found" instead.