Certification Success - Windows Server 2003 Schema

The Schema is a representation of the contents that can be stored within Active Directory. It’s made up of classes, attributes, and class properties. It defines the different kinds of objects and the information associated with each type of object that can be stored in Active Directory.

The Schema is made up of two different components: class-schema objects and attribute-schema objects. The object classes define the specific types of objects that can be created. The attribute class defines the different information for each object type. Each attribute is only defined once within the Schema but can be associated with multiple object classes.

For example, one type of object class that can be created in Active Directory is a user account. When you create a user account, you’ll notice many configurable options from the user account’s properties dialog box. These are all attributes that have been defined within the Schema, such the email address associated with the user account. Some of the attributes are required such as the logon name for the user account and other attributes, such as the business telephone number are optional.

When you install Active Directory for the first time, a default schema is created that contains a basic set of object classes and attributes. Experienced programmers and network administrators can extend the schema if all the required object classes and attribute classes are not present.

Some software that integrates within Active Directory will extend the schema during its installation to add additional object and attributes. An example of this would be the installation of ISA Server 2000. ISA Server arrays use Active Directory to store configuration information. One of the steps in configuring an ISA Server array is to run the Enterprise Initialization Tool to add the ISA Server related objects and attributes to the schema.

It is important to remember as well that you must be a member of the Schema Admins group in order to perform any updates to the Schema.

The following steps outline how to add the Active Directory Schema snap-in and view the attributes associated with the User class object.

1. Within Windows Explorer, locate the schmmgmt.dll and regsvr32.exe (both are located in the Windows\system32 directory).

2. Drag the schmmgmt.dll onto the regsvr32.exe. A Window should appear telling you that the operation was successful. Click OK.
3. Click Start and click Run. Type mmc and press Enter.
4. Within the management console click file and click Add/Remove Snap-in. Click Add and scroll the list of snap-ins.
5. Select the Active Directory Schema. Click Add and click Close. Click Ok.
6. In the left pane, expand the Active Directory Schema and click the Classes container. Scroll through the list available classes in the right pane. Notice the default object classes available.
7. Double click the User class object. This brings up the User Properties window.
8. Click on the Attributes tab to view which attributes are associated with the user class.
9. Click Cancel and close the Active Directory Schema snap-in.