DNS Administrative Domains

From a DNS perspective, an administrative domain is a group of machines which are administered as a unit. Information about this domain is maintained by at least two name servers, which are “authoritative” for the domain. The DNS domain is a logical grouping of machines. The domain groupings could correspond to a physical grouping of machines, such as all machines attached to the Ethernet in a small business. Similarly, a local DNS domain could include all machines on a vast university network that belong to the computer science department or to university administration.

For example, suppose the Ajax company has two sites, in San Francisco and in Seattle. The Retail.Sales.Ajax.com. domain is in Seattle. The Wholesale.Sales.Ajax.com. domain is in San Francisco. One part of the Sales.Ajax.com. domain would be in one city, the other part in the second city.

Each administrative domain must have its own unique subdomain name. Moreover, if you want your network to participate in the Internet, the network must be part of a registered administrative domain. The section Joining the Internet has full details about domain names and domain registration.