Reverse IP Lookup
Find the PTR (reverse DNS) hostname associated with an IP address or domain.
Enter an IPv4 or IPv6 address, or a domain name to resolve first.
About this tool
Reverse DNS maps an IP address back to a hostname via a PTR record — the opposite of a normal ("forward") DNS lookup, which maps a domain name to an IP address. Not every IP has a PTR record configured; many residential and cloud IPs are left with a generic ISP or hosting-provider hostname, or no PTR record at all.
Why reverse IP lookups matter
- Email deliverability — most mail servers check that a sending IP has a PTR record that roughly matches its sending domain before accepting mail. A missing or mismatched PTR record is a common reason legitimate email lands in spam.
- Network troubleshooting — server logs and firewall rules often only show raw IPs; reverse lookup helps identify what's actually behind a connection.
- Verifying server identity — confirming that traffic really is coming from (or going to) the server you expect, such as checking a bot claims to be Googlebot legitimately.
Reverse lookup vs. forward lookup
A forward lookup starts with a domain and returns an IP (what the main
DNS Lookup tool does with an A/AAAA record). A reverse lookup starts with an
IP and returns a hostname, using the special in-addr.arpa (IPv4) or ip6.arpa
(IPv6) zone that mirrors the internet's address space back to hostnames.
Why does my reverse lookup show no PTR record?
PTR records must be configured by whoever controls the IP address block — usually a hosting provider or ISP — not by the domain owner. Shared hosting and many consumer connections simply don't have one set.
Can one IP have multiple reverse hostnames?
Technically a PTR record can list more than one hostname, but in practice almost every IP is configured with exactly one canonical reverse hostname.
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