RIPE's WHOIS service gives contact and registration information for IP addresses, autonomous system numbers (ASN), organizations or customers that are associated with these resources, and related Points of Contact (POC). It doesn't include information on domain names.

ARIN's WHOIS service gives contact and registration information for IP addresses, autonomous system numbers (ASN), organizations or customers that are associated with these resources, and related Points of Contact (POC). It doesn't include information on domain names or military networks.

Get detailed information about an Internet host. Enter an IP address (64.233.167.99), domain name (google.com), hostname (py-in-f99.google.com), or AS-number (AS15169) to get detailed dns information including reverse dns and forwards, whois information, who hosts the machine, and if it's listed in any RBLs (black lists).