Is there a "native mode" for every domain functional level?

Solution 1:

"Native" mode in this context usually means 2000/2003 Native or above. If you're in 2000/2003 mixed mode, then there are certain things that aren't available in order to allow for NT4 Domain Controllers.

Verify with the vendor, but it's a safe bet to assume that anything 2000 native, 2003 native, or higher is fine.

Solution 2:

The requirement that "Active Directory must be configured in native mode" really means that no domain or forest functional level that allows for Windows NT domain controllers (Windows 2000 mixed or Windows Server 2003 interim) is acceptable. Since domain/forest functional levels of Windows Server 2003 and beyond don't support Windows NT domain controllers the unspoken implication is that these domain functional levels are "native".