American Registry for Internet Numbers
ARIN is the regional registry of IP and ASN numbers for North America, South America, the Caribbean, and sub-Saharan Africa.

Asia Pacific Network Information Centre
Regional Internet Registry that allocates IP and AS numbers in the Asia Pacific region. Has a "whois" database that holds information on network contacts for Asia Pacific IP addresses.

Internet Assigned Numbers Authority
IANA controls numbers for protocols, the Country Code Top Level Domains and maintains the IP Address allotments.

Latin American and Caribbean IP address Regional Registry
Responsible registry for south america.

RIPE Network Coordination Centre
Responsible registry for europe, north africa and russian area.