domains

a domain is a logical grouping of network computers that share central directory database. a directory database contains user accounts and security informations for the domain.this database known as the directory and is the database portion of active directory service.

in a domain the directory resides on computers that are configured as domain controllers. a domain controller is a server that manages all security related aspects of user and domain interactions, centralizing security and administration.

the steps in the authentication process are as follows

• the user logs on by providing logon information, such as username and password, and windows xp professional forwards this information to the security subsystem of that local computer.
• windows xp professional compares the logon informations with the user informations in the local security database, which resides in the security subsystem of the local computer.
• if the information matches and the user account is valid, windows xp professional creates access token for the user. an access token is the users identification for that local computer. it contains the users security settings, which allow the user to gain access to the appropriate resources on that computer and to perform specific system tasks.

if a user logs on to a domain, windows xp professional contacts an available domain controller in the domain. the domain controller compares the logon informations with the user information that is in the directory for the domain. if the information matches and the user account is valid, the domain controller creates an access token for the user. the user security settings contained in the access token allow the user to gain access to the appropriate resources in the domain.