How WHOIS Works
WHOIS is an easy protocol that requests information about domain name ownership. You have the ability to look up domains by their domain name and IP address if you happen to know it. When you research a domain the protocol returns the information to you in a readable format. You type in the name of the domain you are asking about which accesses the proper database to find out if the domain name is available or if it is already registered to someone. This is what we call a WHOIS search.
If the domain name is not registered it will have a status stating that it is available. If it not available it will give you a different status ranging from registered, on hold, blocked, reserved or quarantined. If the domain name is registered it will return with additional information such as the name of the individual, e-mail address and the language they wish to be contacted in. If the domain name is registered to a company it will give you information such as the physical address, phone and fax number.
The Databases Required
Databases of WHOIS records are kept by domain registrars.These databases consist of what are called top-level domain databases. Every database includes text records for every resource. Each database handles a WHOIS query differently and the format is different as well. Some databases require two stages to look up the information while many just go directly to the proper database. Some top-level domains include .com, .net, .name, .gov, .me, .eu, .uk, .usa just to name a few. There are thousands of databases based on the ending of the domain name. Most of the WHOIS databases are handled VeriSign.
[Read more about domain registration at the American Registry for Internet Numbers (ARIN).
DNS versus Whois
The DNS is short for domain name system. DNS is only used to find the communication address of electronic devices. In contrast, Whois actually determines information about the domain owner and registrar. The Whois information, however, will include information about the domain's name servers. The name servers hold the information about the domain's IP address.
[Want to find out how DNS works? Use the DNS Lookup Tool.]