Zoho Banner September 2011

There seems to be a certain amount of confusion surrounding Domain and Forest functional levels.  Microsoft’s own documentation doesn’t always incorporate the latest version information.  KB322692 is a case in point.  I also often hear the words “Native” and “Mixed” in relation to functional levels involving Windows Server 2003 or 2008, when in fact these terms are only relevant in the context of Windows 2000 Server.  Anyway, in an effort to clarify the situation and to avoid confusion I put together the tables below. 

  

Domain Functional Level

Numeric

DCs Supported
Windows 2000 Mixed

0

Windows NT 4.0
Windows 2000 Server
Windows Server 2003
Windows 2000 Native

0

Windows Server 2000
Windows Server 2003
Windows Server 2008
Windows Server 2008 R2
Windows Server 2003 Interim

1

Windows NT 4.0
Windows Server 2003
Windows Server 2003

2

Windows Server 2003
Windows Server 2008
Windows Server 2008 R2
Windows Server 2008

3

Windows Server 2008
Windows Server 2008 R2
Windows Server 2008 R2

4

Windows Server 2008 R2

 

Forest Functional Level

Numeric

DCs Supported
Windows 2000

0

Windows NT 4.0
Windows Server 2000
Windows Server 2003
Windows Server 2008
Windows Server 2008 R2
Windows Server 2003 Interim

1

Windows NT 4.0
Windows Server 2003
Windows Server 2003

2

Windows Server 2003
Windows Server 2008
Windows Server 2008 R2
Windows Server 2008

3

Windows Server 2008
Windows Server 2008 R2
Windows Server 2008 R2

4

Windows Server 2008 R2

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