The WHOIS information of a domain name is a collection of many details which are publicly accessed via special lookup websites or a command line. The protocol which makes this possible has the same name and you may effortlessly see the company through which a domain address has been registered, the creation, expiration and last update dates along with the names, postal and email address of the individuals listed as Registrant (owner), Administrative, Technical and Billing contacts for a particular domain. All this information should be correct and up-to-date at all times; otherwise the domain registration can be challenged. The latter is a policy of ICANN (the Internet Corporation for Assigned Names and Numbers), this means you should always ensure that the WHOIS details of your domain addresses are valid. Updating the WHOIS for several country-code TLDs is limited, so whenever you register a new domain name, it is best to double-check the information you're submitting.