As the domain name is unique, there must be some central authority to manage the registration of the domains in order to make domain name unique. ICANN is a central authority for registering domains. ICANN stands for Internet Corporation for Assigned Names and Numbers. ICAAN is responsible for the global co-ordination of Internet’s systems of unique identifiers (e.g. domain names). ICANN gives an accreditation to other companies to register domains. These companies are called registrars. ICANN develops policies that ensure the Internet’s on-going security and stability.