The WHOIS information of a domain is a collection of various details which are openly accessed via specific lookup Internet sites or a command line. The protocol that makes this possible bears the same name and you can easily see the organization through which a domain name has been registered, the creation, expiration and last update dates in addition to the names, postal and email address of the individuals listed as Registrant (owner), Administrative, Technical and Billing contacts for a particular domain address. This info should be valid and up-to-date all the time; otherwise the domain registration could be challenged. The latter is a policy of ICANN (the Internet Corporation for Assigned Names and Numbers), this means you must always ensure that the WHOIS details of your domain addresses are valid. Updating the WHOIS for numerous country-code TLDs is limited, so when you register a brand new domain, it is best to double-check the information that you're submitting.