Servers within the domain advertise their services to users. Users who log in to a domain gain access to all resources in the domain for which they have been granted access. When networks become large enough to require several domains, administrators can establish trust relationships among domains. Trust relationships simplify administration, because a user is required to have an account in only one domain. Other domains that trust the user's logon domain can rely on the logon domain to authenticate the user's logon.
Domains are essentially improved workgroups.
Access to domain resources is controlled by a domain controller. The user is assigned a single domain account and a password to control access to all domain resources. NT Server domains also support the use of groups that enable administrators to assign and change permissions for large numbers of users efficiently. The User Manager for Domains utility is used to maintain user and group information for the domain. This information is stored in a domain security database on the primary domain controller.