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Run a reverse IP lookup by entering any IPv4 or IPv6 address to discover every domain that resolves to it. Map shared hosting, CDN footprints, and co-tenant infrastructure in seconds.
DNS itself has no built-in way to answer this question. A resolver can only travel from domain to record, not the other way around, and PTR records return at most one canonical hostname per address. Reverse IP lookups are made possible by large passive DNS datasets that index A and AAAA records across the internet, then let you query that index in reverse.
When you run a search, the tool queries an indexed database of DNS records collected from domains across the global DNS. It matches your address against the record value of every stored A and AAAA record and returns the domains that resolve to it.
The address you enter determines which record type is searched:
| Input | Record Type Searched | What It Matches |
|---|---|---|
| 8.8.8.8 | A | Domains whose IPv4 A record resolves to 8.8.8.8 |
| 2001:4860:4860::8888 | AAAA | Domains whose IPv6 AAAA record resolves to that address |
Input is validated before the request is sent, so anything that is not a well-formed IPv4 or IPv6 address is rejected in the form with a clear message.
| DNS Lookup | Reverse IP Lookup | |
|---|---|---|
| Input | A domain name (example.com) | An IP address (203.0.113.10) |
| Output | The A and AAAA records for that domain | All domains resolving to that address |
| Data source | Live DNS query against authoritative name servers | Indexed passive DNS database |
| Primary use | Verifying where a domain points | Infrastructure mapping, security research, and investigations |
Forgotten A records pointing at decommissioned or reassigned addresses are a known subdomain-takeover vector. Searching your organisation's server addresses surfaces old or orphaned hostnames still resolving to your infrastructure, so you can clean them up before someone else claims them.
After moving to a new host or CDN, a reverse IP lookup on the old address shows which of your hostnames are still pointing at it. It is a fast way to catch subdomains that were missed during a cutover before they start serving stale content.
An A record maps a hostname to an IPv4 address, and an AAAA record maps it to an IPv6 address. Each record carries a TTL that tells resolvers how long to cache it. A single domain can list several addresses for redundancy, and thousands of domains can point at the same address, which is exactly the relationship a reverse IP lookup uncovers.
A reverse DNS lookup resolves an IP address to one hostname using PTR records, which you can test with our IP to hostname lookup. A reverse IP lookup searches an indexed database to find every domain pointing at that address. They answer different questions using different data.