Whois Lookup is a free online tool which can be used to query Whois records for any domain name.
WHOIS (Engl. "Who is?" - "Who is this?") - the protocol, through which you can get information about a domain name or an IP-address.
Using WHOIS you can see whether the domain is busy, and find out the contact details of domain owner, creation date, expiration date, registration and more.
All this information is public, but some registrars allow direct contacts to hide the domain owner. In this case, the company will be listed contacts registrar.
In computers running Linux or Mac OS utility WHOIS usually installed by default.
In this case, to make the WHOIS query is enough to execute a command in the terminal:
whois <domain name or IP-address>
WHOIS query is performed to a special server, which stores information about the domain and range of IP addresses. WHOIS protocol itself runs on a 43-m port, which can be determined by using the base port(port 43 check) .