Reverse DNS Lookup
Enter an IPv4 or IPv6 address to find the hostname it points back to. This tool builds the reverse pointer name and queries its PTR record over DNS over HTTPS.
Turning an IP back into a name
Normal DNS goes forwards: you give it example.com and it hands back an IP address. Reverse DNS goes the other way — you give it an IP address and it tells you the hostname configured for it. It does this with a PTR ("pointer") record stored under a special reverse zone. For IPv4 the address is reversed and placed under in-addr.arpa (so 8.8.4.4 becomes 4.4.8.8.in-addr.arpa); for IPv6 each nibble is reversed under ip6.arpa. This tool builds that name for you and queries its PTR record via Google's DNS-over-HTTPS resolver. For the full story, read reverse DNS and PTR records.
Reverse DNS is optional and is set by whoever controls the IP block, not the website owner. Many addresses — especially home, mobile and some cloud IPs — have no PTR record at all, so "no PTR record" simply means none was configured. It does not indicate a problem. This lookup, like the others here, is sent from your browser to a third-party public resolver.
Reverse DNS matters most for email: mail servers routinely check that a sending IP has a matching PTR record and often reject mail that does not, as a basic anti-spam signal. It also makes logs, DNS diagnostics and traceroutes much easier to read by showing recognisable names in place of bare numbers. Want to go the other direction and resolve a name to its records? Use the DNS Lookup tool. To see which mail servers a domain uses, try the MX Record Lookup.
Frequently asked questions
What is a reverse DNS (PTR) lookup?
A reverse DNS lookup takes an IP address and asks which hostname it maps back to, using a special PTR record. Forward DNS turns a name into an address; reverse DNS turns an address into a name. This tool builds the in-addr.arpa (IPv4) or ip6.arpa (IPv6) query name and looks up its PTR record.
Why does an IP have no PTR record?
Reverse DNS is optional and is controlled by whoever owns the address block, not by the website owner. Many home and mobile IPs, and plenty of servers, simply have no PTR record configured — so a blank result is normal and does not mean anything is wrong.
Does the PTR always match the website's domain?
Not necessarily. The PTR is set by the network operator and often points to a generic hosting or ISP name (like a datacentre hostname) rather than the site you expect. A forward lookup of that hostname should resolve back to the same IP if reverse DNS is set up correctly.
Where is reverse DNS used?
It is widely used in email anti-spam checks — many mail servers reject or distrust senders whose IP has no matching reverse DNS — and it makes server logs, traceroutes and diagnostics far more readable by showing names instead of raw numbers.
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