What is Active Directory A directory service from Microsoft that is a part of Windows 2000. It is an implementation of Internet standard directory and naming protocols that uses a database engine for transactional support, and also supports a variety of application programming interface standards. System.DirectoryServices Namespace The System.DirectoryServices namespace provides easy access to Active Directory Domain Services from managed code. The namespace contains two component classes, DirectoryEntry and DirectorySearcher, which use the Active Directory Services Interfaces (ADSI) technology. ADSI is the set of interfaces that Microsoft provides as a flexible tool for working with a variety of network providers. ADSI gives the administrator the ability to locate and manage resources on a network with relative ease, regardless of the size of the network. System.DirectoryServices.ActiveDirecto...