Whois
Whois (pronounced as the phrase who is) is a query and response protocol that is widely used for querying databases that store the registered users or assignees of an Internet resource, such as a domain name, an IP address block, or an autonomous system, but is also used for a wider range of other information [1].
Implementation
Whois is first implemented on UNIX and is available for all operation systems. The implementation may vary in functionality.
Servers
<img title="Regional Internet Registries" size="200" src=http://upload.wikimedia.org/wikipedia/commons/9/95/Regional_Internet_Registries_world_map.svg />
