WHOIS is a database that can be accessed by anyone. A WHOIS database contains the contact information of domain name owners. WHOIS is operated by the Internet Assigned Numbers Authority (IANA). The database was originally created as a way for domain name owners and other interested parties to check who owned certain domain names. The database was established to increase the availability of whois address searches and to help users find information about domain name owners and their contact information.
WHOIS is a self-explanatory database. A WHOIS client connects through an IP address to a WHOIS server. The WHOIS database contains information such as the full name of the domain owner, the current address of the domain, the expiration date of the registration, and the telephone number of the owner. There are also other information that may be listed in the WHOIS database, depending on the extent of the registration and any applicable policies. WHOIS is updated periodically and the database is subject to constant updating.
Video Source : Passive Reconnaissance – Whois Lookup Tutorial
WHOIS is a part of the ICANN group of organizations responsible for managing the DNS system. ICANN is a United States cooperative agency composed of diverse international member companies. The responsibilities of ICANN include managing the DNS system to allow for reasonable access to the internet and disseminate technical support. ICANN oversees the WHOIS project and maintains the WHOIS database. ICANN updates the WHOIS database on a regular basis
Users of the WHOIS database can search the WHOIS database for domain names and contact details of domain owners. When a query is sent via email to WHOIS, the WHOIS service searches the WHOIS database and returns a response such as an acknowledgement with a link to the domain name or a failed query result. WHOIS can be used by anyone to look up domain names and obtain information about domain owners. Any user can make a query about a domain and obtain detailed information such as name, address, registrant, contact details, version of a domain, dates, and other information. WHOIS is used by online public authorities, educational institutions, businesses, and individuals to get reliable information about domain names.
If you every looking for who the own of a domain name or website is you can consult the Whois database. However is some cases domain owners may turn on a special feature called “Domain Privacy” which blocks out the a domain owners contact details.