DirSync (Windows Azure Active Directory Sync)
DirSync (Directory Synchronization) is a tool for making copies of a local directory in a hybrid cloud deployment of Microsoft Exchange.
DirSync makes a copy of the local directory and then propagates itself to a Windows Azure cloud tenant Active Directory instance. After that, DirSync runs every three hours to push changes from the on-premises directory to the cloud instance. DirSync only goes from on-premises to cloud. If an administrator were to create a new user on the Windows Azure Active Directory tenant, that user would live only in the cloud and would never be propagated down to the on-premises directory.
DirSync works with Office 365 and Windows Azure Active Directory, removing the need for Active Directory Federation Services in many organizations.
