Reverse DNS Lookup

Find the reverse DNS hostname associated with a public IPv4 or IPv6 address.

A reverse DNS lookup starts with an IP address and checks for PTR records that map the address back to one or more hostnames. Network owners control these records through the reverse DNS zone for their address space.

PTR records are commonly used in mail server reputation, infrastructure identification, logging, and diagnostics. A missing record is common and does not mean the IP address is invalid.

How reverse DNS works

Normal DNS maps names to addresses. Reverse DNS uses special in-addr.arpa or ip6.arpa zones to map IPv4 or IPv6 addresses back to hostnames.

Why email servers check PTR records

Mail systems often compare forward and reverse DNS as one reputation signal. A sensible PTR record can improve clarity, but it does not guarantee email acceptance.

Why a PTR record may be missing

Residential, mobile, shared, and temporary address ranges often have generic or no PTR records. Only the address owner or provider can normally change reverse DNS.

What the result proves

A PTR result identifies a hostname published by the network owner. It does not prove who is using the address or what service is running there.

Frequently Asked Questions

What is a PTR record?

A PTR record maps an IP address to a hostname in reverse DNS.

Can I set reverse DNS myself?

Usually only the ISP, hosting provider, or owner of the IP range can set it.

Is reverse DNS the same as IP geolocation?

No. Reverse DNS returns a hostname, while geolocation estimates a network location.