How to Raise Domain Functional Level in Windows Server 2003?

Domain functional level is a state of domain which offers better functionalities to the users and the administrators. If domain functional level is at the lower state it does not provide much features is but enables backward compatibility which can be useful in the networks having multiple older versions of Windows servers. When domain functional level is raised it starts providing better features however it does not provide backward compatibility benefits. In other words it can be said the higher the domain functional level is the better features administrators can experience. And the lower the domain functional level is the better are the chances to make the domain environment backward compatible with older versions of Windows servers. You can raise domain functional level by following the steps given below:

1. Log on to the domain controller with administrator privileges.
2. Click on Start button.
3. From the start menu go to Administrative Tools and from the submenu click on Active Directory Users and Computers.
4. From Active Directory Users and Computers snap-in right click on the domain name which in this case is TESTDOMAIN.COM.
5. From the context menu click on Raise Domain Functional Level.
6. On Raise Domain Functional Level box from the drop-down list choose the appropriate domain functional level as required and click on Raise button.
7. 
8. On the confirmation box click on Ok button to confirm the task and click on Ok button again on the appeared box.
9. Close Active Directory Users and Computers snap-in.

Note:

• Raising domain functional level is one-way process which cannot be reverted back. This means that once a domain functional level is raised you cannot downgrade the domain functional level.
• Default domain functional level is Windows 2000 (Mixed) mode.

More Info:

• It is always recommended to raise domain functional level to Windows Server 2003 if all the domain controllers in a domain are running Windows server 2003 servers.