The WHOIS information of an domain name is a collection of a number of details which are openly accessed using special lookup sites or a command line. The protocol that makes this possible bears the same name and you could effortlessly see the organization where a domain has been registered, the creation, expiration and last update dates together with the names, postal and e-mail address of those listed as Registrant (owner), Administrative, Technical and Billing contacts for a specific domain. This information has to be correct and up-to-date at all times; if it's not the Internet domain registration could be challenged. The latter is a policy of ICANN (the Internet Corporation for Assigned Names and Numbers), so you should always ensure that the WHOIS details of your domain addresses are valid. Updating the WHOIS for a variety of country-code TLDs is limited, so any time you register a completely new domain, it is best to double-check the information that you are submitting.