DNS Zone - Second-level Domains

Second-level Domains

Many top-level registries open up their name spaces to the public or to entities with mandated geographic or otherwise scoped purpose for registration of second-level domains. Each one of these registrations obligates the registrant to maintain an administrative and technical infrastructure to manage the responsibility for its zone, including sub-delegation to lower-level domains. Each delegation confers essentially unrestricted autonomy over the allocated space. As each zone is further divided into sub-domains, each becoming a DNS zone itself with its own set of administrators and DNS servers, the tree grows with the largest number of leaf nodes at the bottom. At this lowest level, in the end-nodes or leaves of the tree, the term DNS zone becomes essentially synonymous, both in terms of use and administration, with the term "domain". The term domain is used in the business functions of the entity assigned to it and the term zone is usually used for configuration of DNS services.