It is too difficult to remember IP addresses hence domain names have come into the picture. Domain names are associated with the websites and resolve into the assigned number. It is essential to register a domain name for a website.
In order to connect domain name to the associated IP address DNS or domain name service is required. The service keeps track of domain names and their associated IP addresses. The DNS servers contain a section of the domain database and whence the right address is not located in the server the request is diverted to another till eventually the corresponding IP address is located.
In case of a registered domain name the address is clubbed with the IP address of the hosting sever where the directory resides. This how a website becomes visible to us upon request. Whence a domain name is typed on the address bar of the browser a request is made to the DNS server clubbed with it.
While configuring TCP/IP a primary DNS number is assigned which is actually a getaway to number of name servers which makes search possible for the right IP address.
Domain Name Registration
In order to register a domain name one needs service of a domain registrar who registers the name at ICANN. A fee is involved which you have to pay to the registrar for one year or more depending upon you. After the expiry period your site will not be visible since the associated name is no longer yours. Anyway you get forty five days to renew the name else it goes to an open pool such that anyone can register it in his own name.
These sites provide complete details of the domain name. The name of the registrant his address and contact details. The name server details are also available. The date of registration, date of updating and expiry can also be found.