Exchange Resource Forest Management requires Exchange 2013 or later to be deployed in the Exchange forest.
Exchange Server should not be installed in the accounts forests. The Active Directory schema in the accounts forests does not need to be extended with the Exchange Server attributes.
A trust between the Exchange forest and the accounts forest must be set up before you can use Exchange Resource Forest Management. At a minimum, an outgoing trust must be set up so that the Exchange forest trusts the accounts forest.
For more information, see "Learn more about setting up a forest trust to support linked mailboxes" at http://technet.microsoft.com/library/ms.exch.eac.trustedforestordomainlearnmore(v=exchg.150).aspx.
The following Active Roles components must be installed in your Active Directory environment:
To configure Exchange Resource Forest Management, log on as Active Roles Admin. This ensures that you have sufficient rights to make the necessary configuration changes. Assuming the default configuration of the Active Roles Administration Service, you should log on with a domain user account that is a member of the Administrators group on the computer running the Administration Service.