Active Directory (AD):
is a directory service that Microsoft developed for Windows domain networks. It is included in most Windows Server operating systems as a set of processes and services. Initially, Active Directory was only in charge of centralized domain management. Starting with Windows Server 2008, however, Active Directory became an umbrella title for a broad range of directory-based identity-related services.
A server running Active Directory Domain Services (AD DS) is called a domain controller. It authenticates and authorizes all users and computers in a Windows domain type network—assigning and enforcing security policies for all computers and installing or updating software. For example, when a user logs into a computer that is part of a Windows domain, Active Directory checks the submitted password and determines whether the user is a system administrator or normal user. Also, it allows management and storage of information at admin level and provides authentication and authorization mechanisms and a framework to deploy other related services (AD Certificate Services, AD Federated Services, etc.).
Active Directory features include:
- Support for the X.500 standard for global directories
- The capability for secure extension of network operations to the Web
- A hierarchical organization that provides a single point of access for system administration (management of user accounts, clients, servers, and applications, for example) to reduce redundancy and errors
- An object-oriented storage organization, which allows easier access to information
- Support for the Lightweight Directory Access Protocol (LDAP) to enable inter-directory operability
- Designed to be both backward compatible and forward compatible