The Active Directory consists of the database and the Active Directory servcie running it. Its main purpose is to provide authentication and authorization services for computers running Windows, allowing centralized administration of all published resources on the network (files, shares, peripherals, connections, databases, users, groups, etc.) – or decentralized management by delegating administrator privileges. It provides access to many different resources (shared folders, printers, mail, etc.) by entering a single username / password pair (SSO). It allows administrators to assign policies and install software and software updates within the organization. Active Directory stores information and settings in a central database on the domain controller computer(s). The size of this database can range from a few hundred objects in a small business to many millions of objects in an international company running thousands of servers. Active Directory requires some Windows components, such as Exchange, RRAS, ISA Server, or Certificate Services.
