I have two forests, forest A, forest B.
Forest A has no Exchange server. Forest B has 2010 Enterprise.
Forest A does not trust Forest B. Forest B does trust Forest A.
The users are in Forest A, and I want Forest B to use those users in A and give them mailboxes in the B Exchange server but authenticate with A's domain controller.
Is this possible? If so how can I do it?
I cannot use Federation Services because I only have one 2010 Exchange server and it is in Forest B.