Active Directory is a proprietary directory service developed by Microsoft® to provide secure access to corporate networks. Active Directory stores information related to user accounts, computer objects, groups, policies and other resources on the network. It also provides an efficient way for administrators to manage the security settings of their organization’s IT infrastructure.

AD was developed to manage the authentication and authorization of users and machines on a Windows domain network.

With Active Directory, administrators can easily control who has access to what resources on the network. They can also set up automated processes for managing user and computer permissions across multiple systems with ease.

Active Directory was first released in 2000 and runs on Windows Server. Since then, it has become the umbrella brand for a broad assortment of directory-based identity services from Microsoft.

Microsoft introduced Azure AD to support cloud-hosted infrastructures. Azure AD Connect was then introduced to help bridge the on-prem AD with cloud-hosted Azure AD.