Whois 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. The protocol stores and delivers database content in a human-readable format. More informations on Wikipedia.
This tool will help you to find administrative information about domaine name, IP addresses or AS number. In the following form you can enter differents queries: