Reverse DNS Lookup (PTR Record)
Enter any IPv4 or IPv6 address below to find its PTR record — the hostname its owner registered for it. The lookup runs from your browser via encrypted DNS over HTTPS (Cloudflare 1.1.1.1).
What is reverse DNS?
Normal DNS turns a name into an IP address; reverse DNS goes the other
way. Each IP can have a PTR record: IPv4 addresses under the special
in-addr.arpa zone (the octets reversed, so 8.8.8.8 becomes
8.8.8.8.in-addr.arpa) and IPv6 addresses under ip6.arpa, spelled
out as 32 reversed hexadecimal nibbles. Only the network that owns the IP can publish its
PTR record.
What PTR records are used for
- Mail delivery: many mail servers penalize or reject email from IPs without a matching PTR record — it is a basic anti-spam check.
- Log readability: servers resolve visitor IPs to hostnames like
host-1-2-3-4.isp.example, which often names the ISP. - Network debugging:
tracerouteshows router hostnames via reverse DNS.
Many home and mobile IPs have generic PTR names or none at all — "no PTR record" is completely normal for consumer connections.
Related tools
Pair a PTR lookup with an ASN lookup to see who operates the network, run a full IP lookup for location details, or check your own IP first.