Active Directory (AD) is Microsoft’s directory service used for managing and authenticating users, computers, and resources in a Windows network. It provides centralized authentication, authorization, and policy enforcement, allowing administrators to control access to files, applications, and network resources. AD is built on Lightweight Directory Access Protocol (LDAP) and integrates with Kerberos for secure authentication. The core component, Active Directory Domain Services (AD DS), organizes objects (users, groups, computers) into a structured hierarchy, including domains, organizational units (OUs), trees, and forests. AD is essential for enterprise IT environments, enabling single sign-on (SSO), Group Policy enforcement, and security management. Learn more: https://en.wikipedia.org/wiki/Active_Directory