IP addresses and networks
Reverse DNS: pointer (PTR) record
Reverse DNS maps an IP address back to a hostname, using a PTR record, the opposite direction of an ordinary DNS lookup.
How it works
The owner of an address block controls its reverse records. Mail servers commonly check that a sending address has a sensible reverse name, and that the name resolves back to the same address.
A hostname such as one that names a cloud provider or a home internet service gives another clue about what sits behind an IP address.
Related LookValid products
| Product | Credits | Docs |
|---|---|---|
| IP Intelligence | 1 credit per lookup | API docs |
| Reverse IP Append | 10 credits per match (no match is free) | Product page |
New to the API? Start with the quickstart or the API reference. Agents can call the same lookups through the MCP server.