If you only need to track one or two additional attributes for your employees, you might decide to simply link the existing Employee-ID and Employee-Number attributes to the user class. For example, the Employee-ID attribute could be used to store a company-specific alphanumeric and the Employee-Number attribute could be used to store tax identifiers, such as social security number (SSNs) for the United States or social insurance number (SIN) for Canada.
Here's how you add a social security number attribute to the Active Directory schema, but the steps are applicable to adding other attributes as well:
With the Schema console open, expand the Active Directory Schema snap-in and then click the Attributes node. A list of attributes appears in the right pane.
Right-click the Attributes node and click Create Attribute on the context menu (see Figure 4).
A Schema Object Creation message appears, reminding you that this is a one-way operation. The attribute can be disabled later, but it can't be undone without reinstalling all domain controllers on your enterprise network. (Of course, you should be trying this on a test domain controller to be sure that everything works before you ever consider performing these steps on your production domain controllers.) If you want to proceed, click Continue.
The Create New Attribute dialog box appears. Configure the settings as shown in Figure 5.
Click OK. The SSN attribute is added to the list. If you click in the right pane and type S, the SSN attribute will be selected.
Figure 4 Active Directory Schema attributes.
Figure 5 Creating a new attribute.
The Unique X.500 Object ID setting is a predefined value. If you need object IDs for additional classes or attributes, visit the Microsoft web site for details.