What is WHOIS
WHOIS is a protocol that is used to display information about domains, including the domain’s registrar, domain creation and update dates, and contact information. WHOIS servers are usually operated by the five major regional Internet registries, or RIRs. Each RIR serves a major geographic region, such as a continent. In addition to the RIR WHOIS servers, some private databases exist. WHOIS information is available to anyone with Internet access with a WHOIS domain search. However, no specific purpose is set forth in RFC 3912 (WHOIS Protocol Specification).
WHOIS record information has become inherently useful to law enforcement agencies and Internet service providers (ISPs) in investigating complaints and alleged crime involving websites. While the information in a WHOIS record can be falsified, a number of steps have been put into place to aid in verifying the information. However, WHOIS information should usually not be treated as inherently accurate.
WHOIS information can also provide a level of assurance that a website is reliable, by providing information for making direct contact with the individuals or organization operating the website. Phone numbers, addresses, and other information found in a domain search can help to verify the website’s identity.
One third and major purpose of WHOIS record information is useful to potential domain users. If a user is interested in purchasing a domain name, WHOIS records can be used to determine if that domain has already been registered. If it has, WHOIS records also give insight as to when the domain name might expire and be available again for registration.
Drawbacks to WHOIS
The WHOIS protocol was designed for open access. As such, the information presented in a domain search is usually in plain-text and available with little or no restriction. Privacy has become a concern of many domain registrants. As such, some registrars provide a private registration service. In this situation, the registrar or private registration provider assumes the role of the contact entity, sitting between the actual domain user and the outside world.
Domain registrants whose contact information is visible in the WHOIS query are susceptible to unsolicited advertisement, including e-mail spam. Many WHOIS query websites require the visitor to agree to use the information in lawful ways, and to not use the information for the purposes of advertisement or spam. Disclaimers and warnings are often presented in the results of a WHOIS query to help deter misuse.
Using the WHOIS Domain Search
While some computer systems have software that allows direct querying of WHOIS, most personal computers and laptops do not. Therefore, many online services have been created specifically querying for WHOIS information. A web search for "WHOIS" will turn up many options for running a WHOIS domain search.
To use an online WHOIS search, simply enter the domain name of the website. If the domain name is registered, you will be presented with information contained in the WHOIS record. Some WHOIS searches may turn up more information than others. This is due to the design of WHOIS and is based on what database or server the WHOIS search website uses. Additionally, there may be more than one contact category (i.e.: separate administrative and technical contacts).
RFC 3912 – https://tools.ietf.org/html/rfc3912