Windows Server Cookbook

Appendix C. Introduction to ADSI

In February 1997, Microsoft released a set of generic interfaces, called the Active Directory Service Interfaces (ADSI), to access and manipulate different directory services. ADSI is a collection of classes and methods that allows developers using any language that supports the component object model (COM) to access and manipulate objects on workstations and servers or in a directory service, such as Active Directory. Contrary to its name, it was written to be generic and extensible rather than specific to Active Directory. This means that developers can write code to access objects on various directory servers without the need to know vendor-specific library routines or APIs. ADSI is also extensible so developers of other directory services can write the underlying Dynamic Link Library (DLL) code that will allow ADSI to interact with their systems. This is possible because Microsoft publishes the specifications that a Directory Service Provider (code that implements the ADSI specification for a particular directory service) must meet to work correctly with ADSI. This means that whenever you call an ADSI procedure or reference any object via ADSI against a valid provider, you can feel confident that the procedure will perform according to ADSI’s formal documentation no matter what the provider is. While there are several directory service provider-specific extensions, ADSI also supports Lightweight Directory Access Protocol (LDAP), which provides ...