Raising the Domain's Functional Level
To manage domains and trusts with AD, select Active Directory Domains and Trusts from the Administrative Tools program group. The AD Domains and Trusts snap-in should appear with your domain controller(s) listed in the left pane (see Figure 1). The Domains and Trusts snap-in is a convenient way for any administrator to manage multiple AD domains from a single location. Figure 1 shows only one AD domain on my network, but there could easily be several, and I could manage any one of these AD domains from here as necessary.
Figure 1 Domains and Trusts management console.
So what's new with AD 1.1 Domains and Trusts? A new option has been added, allowing you to raise the domain's functional level so that any new AD features deployed with AD 1.1 will be available as soon as all domain controllers are running Windows Server 2003 (see Figure 2).
You should raise your domain functional level to Windows Server 2003 only when all domain controllers on your network are running the Windows Server 2003 operating system. If you still have any Windows 2000 domain controllers, as many places do, stay with the default setting, Windows 2000 native mode. If you're running in Windows 2000 native mode, only AD 1.0 features will be available. In other words, your network AD will operate only at the lowest level of server software; if a Windows 2000 server on your network acts as a domain controller, you'll only get AD 1.0 functionality.
Figure 2 Raising the domain's functional level.