Reverse DNS Lookup (PTR)
Look up the PTR (reverse DNS) record for any IPv4 or IPv6 address. Powered by Cloudflare DoH.
About Reverse DNS Lookup (PTR)
The Reverse DNS Lookup tool finds the PTR record for an IP address, which maps the address back to a hostname. Enter any IPv4 or IPv6 address and the tool reports the hostname associated with it, if one is published.
The IP address you enter is sent to Cloudflare's DNS-over-HTTPS resolver, which performs the PTR query and returns the result shown on the page. Reverse DNS is commonly checked when reviewing mail server configuration or identifying which host an address belongs to in server logs.
Frequently asked questions
- What is a PTR record?
- A PTR record maps an IP address to a hostname, the reverse of the usual name-to-address lookup.
- Why does an address have no reverse DNS?
- PTR records are optional and must be set by whoever controls the address block, so many IPs simply do not have one.
- Why does reverse DNS matter for email?
- Many mail servers check that a sending IP has a valid PTR record, and a missing or mismatched one can hurt deliverability.