Reverse DNS lookup
Find the PTR host name behind any IP address — over DNS-over-HTTPS.
Resolved via DNS-over-HTTPS, proxied through our server. Never stored.
How to do a reverse DNS lookup
- Enter an IP. Type an IPv4 or IPv6 address.
- Resolve the PTR. We query the reverse DNS (PTR) record for that address.
- See the host name. View the host name the IP resolves back to, if one is set.
About reverse DNS
Reverse DNS maps an IP address back to a host name using PTR records stored under the special in-addr.arpa (IPv4) and ip6.arpa (IPv6) zones. It is most important for email: receiving servers often reject or penalize mail from an IP whose PTR record is missing or does not match its forward record. It is also a quick way to identify which provider an address belongs to. Use the IP address lookup to geolocate the address, or a forward DNS lookup to go the other way.
Frequently asked questions
- It finds the host name associated with an IP address by querying its PTR record — the opposite of a normal (forward) DNS lookup that turns a name into an IP.
- PTR records are optional and set by whoever controls the IP block. Many residential and cloud IPs either have none or use a generic provider-assigned name.
- Mail servers check it to reduce spam — a mismatched or missing PTR can hurt deliverability. It also helps identify the network behind an IP during troubleshooting.
- Yes. IPv6 addresses are expanded to their .ip6.arpa form and queried for a PTR record.
- No. The IP is sent to our server, resolved over DNS-over-HTTPS, and the result is returned. Nothing is saved.