Active Directory (AD) is a comprehensive directory service developed by Microsoft, initially introduced in Windows 2000 Server, designed for centralized management of user identities, computing resources, and security policies. Succeeding the legacy Windows NT Domain model, Active Directory supports large-scale enterprise networks and leverages open standards such as DNS (Domain Name System), LDAP (Lightweight Directory Access Protocol), and Kerberos authentication. Its architecture closely aligns with the ITU-T X.500 directory service standard defined by the International Telecommunication Union – Telecommunication Sector (ITU-T), facilitating interoperability and scalability across diverse systems.
Active Directory organizes resources and identities within logical management units known as AD Domains. Each domain centrally manages registered users, computing devices, permissions, authentication processes, and access control. Deployment of Active Directory widely enables organizational single sign-on (SSO), streamlining authentication to multiple internal resources and applications.
Furthermore, solutions such as F5 BIG-IP Access Policy Manager (APM) provide integrated Kerberos authentication, seamlessly interfacing with Active Directory. This integration extends AD-based single sign-on capabilities to legacy devices, web applications, and other resources lacking native AD support, enhancing unified identity and access management across heterogeneous infrastructures.