What is WHOIS?

WHOIS (pronounced "who-is") is a query protocol and set of databases that return registration information about Internet resources: domain names (who registered a domain, when, contact info) and IP address blocks (which RIR allocated it, to which organization, and abuse contact).

The protocol dates to 1982 (RFC 812) and still powers WHOIS lookups today.

For IP addresses, a WHOIS lookup returns:

• The RIR responsible (ARIN, RIPE, APNIC, LACNIC, AfriNIC)
• The allocated CIDR range
• The organization name
• Allocation date
• Abuse contact email (the abuse-c or abuse-mailbox field)

You can run a WHOIS query from any Unix terminal: whois 8.8.8.8. Or use WorldIP.io — we pre-merge WHOIS with MaxMind geolocation so you get everything in one lookup.