WHOIS is a database that consists of mandatory information about a registered domain, or more precisely, the registered users of an Internet resource. A WHOIS information lookup is how we can find a wider range of information on a domain name, an IP address block and the domain availability status. This includes the contact information of the registrant, mailing address, phone number, email address, domain created date, updated date, expiration date as well as the nameservers the domain is using and much more.
Whenever an individual or organization registers a new domain name, the registrar is required to make the registration information publicly available. This is one of the regulations required by Internet Corporation for Assigned Names and Numbers (ICANN). ICANN maintains the database and updates it regularly to ensure the registrant's contact details are valid and up-to-date to help prevent fraud and identity theft. When we perform WHOIS data lookups, WHOIS search engines will look up data across multiple registrars.
Note: While the term is capitalized, "WHOIS" is not an acronym.
It is also called domain privacy. We know how damaging data breaches can be in this century, therefore, businesses take domain privacy protection seriously. WHOIS privacy protection is a service to protect domain registries' personal information from being searched in the WHOIS records.
Under the WHOIS privacy protection, some domain registries allow domain owners to hide certain details in their public WHOIS records. The contact information in a WHOIS record can be hidden from the rest of the world using a "private registration" service offered by some registrars.