DNS Diagnostic Tool

Reverse DNS Lookup

Enter a public IPv4 or IPv6 address to find its PTR hostname. The tool also checks whether that hostname resolves forward to the original IP address.

Check reverse DNS

Use a public IP address. Private and reserved addresses are intentionally blocked.

IP address—
IP version—
Lookup time—
Reverse zone query—

PTR result

What is a reverse DNS lookup?

A normal DNS lookup starts with a hostname and finds an IP address. Reverse DNS does the opposite: it starts with an IP address and asks DNS for a PTR record that names a host associated with that address.

Why PTR records matter

PTR records are often used in email infrastructure, server administration, logging, abuse investigation, and network troubleshooting. Not every public IP has a PTR record, and a missing PTR record does not mean the IP is broken.

Forward-confirmed reverse DNS

This tool also resolves each returned hostname forward. If one of those A or AAAA records points back to the original IP, the result is marked forward confirmed. This is an additional consistency check, not proof of identity or trust.

IPv4 and IPv6 support

IPv4 reverse lookups use the in-addr.arpa DNS zone. IPv6 uses the nibble-based ip6.arpa zone. Fast IP Checking builds the appropriate reverse query automatically.

Reverse DNS FAQ

Can one IP address have more than one PTR record?

DNS can technically return multiple PTR records, although operational guidance generally prefers a clear, stable reverse hostname. This tool displays all PTR results returned by the resolver.

Why does my IP have no reverse DNS?

The network owner may not have configured a PTR record, or the record may not be published correctly. Residential IP addresses often have generic or no meaningful reverse hostnames.

Can I change my PTR record here?

No. Reverse DNS is normally managed by the provider that controls the IP address block. Contact your ISP, hosting provider, or cloud platform if you need to configure it.

Does a matching PTR prove a server is safe?

No. Forward-confirmed reverse DNS only shows DNS consistency. It does not prove ownership, reputation, security, or legitimacy.