If there isn't a Windows NT 4.0 BDC in a Windows 2000 domain, this domain can be switched from the default mixed mode to native mode. In Windows .NET domains, the "functional level" term is used in such a case. You can raise the domain functional level to a level that depends on the types of domain controllers used in the domain. If there are no Windows NT 4.0- or Windows 2000-based domain controllers in the entire Windows .NET forest, it is also possible to raise the forest functional level (see details in Chapter 2, "Active Directory Terminology and Concepts").
Remember that only the type of controllers located in a domain affect the domain mode or level; the domain clients (with or without Active Directory client software) will "see" this level of functionality of an Active Directory domain (see Chapter 2, "Active Directory Terminology and Concepts" for just about the only exception.)
To change a domain mode or functional level, use either snap-in:
Active Directory Users and Computers
Active Directory Domains and Trusts
In the Windows 2000 environment, select a domain and open its Properties window. Click the Change Mode button on the General tab and wait 15 minutes for replication of the changes to all DCs in the domain. Operations in the Windows .NET environment will be described in the "Raising Functional Level" section in Chapter 7, "Domain Manipulation Tools."
To check that the domain is now in the native mode (or at a higher level), you may try to create a universal group or to add a domain local group to another local group.
To view a domain's mode or level, it is convenient to use the Active Directory Domains and Trusts snap-in. You can quickly select any domain and see its mode (level).