Active Directory

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 uses (LDAP) versions 2 and 3, Microsoft's version of , and DNS.

Active Directory, like many information-technology efforts, originated out of a democratization of design using Request for Comments or RFCs. The Internet Engineering Task Force (IETF), which oversees the RFC process, has accepted numerous RFCs initiated by widespread participants. Active Directory incorporates decades of communication technologies into the overarching Active Directory concept then makes improvements upon them. For example, LDAP underpins Active Directory. Also X.500 directories and the Organizational Unit preceded the Active Directory concept that makes use of those methods. The LDAP concept began to emerge even before the founding of Microsoft in April 1975, with RFCs as early as 1971. RFCs contributing to LDAP include RFC 1823 (on the LDAP API, August 1995),RFC 2307, RFC 3062, and RFC 4533.

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