A. The Microsoft article at http://technet.microsoft.com/en-us/library/cc771397.aspx states you can only create a forest trust between a Server 2008/2008 R2 forest and another Server 2008/2008 R2 forest, as shown below.

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This is, in fact, incorrect and Microsoft will update this page to reflect the correct information. You can create a forest trust between any forests that have a forest level of Windows Server 2003 or higher—forest trusts were introduced with Windows Server 2003.

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