Reverse DNS maps an IP address back to a hostname using PTR records in the in-addr.arpa or ip6.arpa zones.

How do I find the hostname of an IP address?

Enter the public IP above and run the reverse DNS lookup. The PTR hostname appears when one is published.

Why is reverse DNS important for email?

Many receiving systems check that the sending IP has a sensible PTR and that forward DNS matches. Missing reverse DNS raises spam scores.

A PTR record is the DNS resource record that stores the reverse hostname for an IP address.

Use this reverse DNS lookup, or query the matching in-addr.arpa name with dig or nslookup. This page does that query for you.

A free online tool that returns PTR hostnames for public IP addresses so students and engineers can verify reverse mappings.

Our server asks public DNS resolvers to reverse the IP you enter, then displays any PTR hostnames that exist.

Paste a public IP, tap Lookup PTR, and read the hostname. Try example chips such as 1.1.1.1 for practice.

Yes. It is free with no sign-up.

Yes. Mobile browsers are supported for on-site IP checks.

Free Reverse DNS Lookup Online, IP to Hostname PTR | Binary Tech