I have an inhouse setup at our office with Sharepoint 2010 installed on Windows Server 2008 R2, a MS SQL Server 2008 on a Windows Server 2008 R2 and a AD Server. I am planning to migrate Sharepoint 2010 and DB Server alone to AWS. I would like to retain my AD server inhouse itself. Now how do I authenticate AD users to Sharepoint Sever. Please consider me as an Windows Newbie.