Hi, Wehave Exchange 2003 clusters running on Windows 2003 servers. The active directory is on Windows 2000 servers. We are considering to upgrade Active Directory to Windows 2008. At this time we do not have any plans to upgrade our Exchange servers. 1. Does this work? 2. What are advantages / disadvantages ? 3. Are there any known issues? 4. Is it wise to upgrade to Windows 2003 instead of Windows 2008 ?

I have not yet tested this, but I think that it is supported. I did a couple of Google searches and found this thread: http://forums.technet.microsoft.com/en-US/winservergen/thread/a7506f72-aba1-44c2-9f30-d5d7c4de8a9b/

I highly recommend you reading below article in the Exchange Team blog. http://msexchangeteam.com/archive/2007/08/16/446709.aspx To upgrade a clustered mailbox server from Windows Server 2003 to Windows Server 2008, you must build a new failover cluster using Windows Server 2008 as the operating system for all nodes, and then migrate the data from the old cluster to the new cluster. You can use the Move Mailbox operation to move mailboxes from the old cluster to the new cluster, and you can use public folder replication to move any public folder data from the old cluster to the new cluster. Jason