When to Extend the IIS ADSI Schema

You should extend the IIS ADSI Schema only if no existing object class meets your needs. Extending the IIS ADSI Schema is a complex operation; schema changes are propagated throughout the namespace. Consider your needs carefully and assess whether an extension is really necessary.

Essentially, there are three ways to extend the IIS ADSI Schema. One way is to add additional properties to an existing class. A second way is to modify the containment list for a class, allowing that class to contain instances of additional existing classes. Finally, a third way is to create an entirely new class with only the properties you want.

Extending an Existing Class

Usually, the best results are obtained by using existing classes. If an existing class needs only additional properties to meet your needs, then simply add the properties. For example, to know when a particular Web site was backed up, you could add a property named LastBackup that would hold a timestamp for that event.

Creating a New Class

Create a new class only when no existing class meets your needs. The best results can be expected by using existing classes. Another reason you might want to create a separate class is for private use.

For the latest information on ADSI, check out the ADSI Web site: http://www.microsoft.com/windows/server/Technical/directory/adsilinks.asp.