4.5 Summary

In this chapter we've shown you how the internal blueprint for all objects in Active Directory, known as the schema, was derived from the X.500 directory service. We explained the purpose of the OID numbering system and how it can be used. We then detailed how an attribute and its syntax is structured in the schema as attributeSchema objects, using the userPrincipalName attribute as an example. We showed how attributes are added to classes by detailing how classes are stored in the schema as instances of classSchema objects. To make this clearer, we dug into the details of the user class to see how it was constructed. Finally, we covered how auxiliary classes can be dynamically linked in Windows Server 2003 and why it is significant.

Chapter 12 builds on what you've learned here to demonstrate how you can design and implement schema extensions.