OABGen

When the Microsoft Exchange System Attendant generates the offline address book (OAB), it calls Oabgen.dll (referred to as OABGen). OABGen is a MAPI application that reads from Active Directory. On a server running Exchange Server 2003 SP2, the first time an OAB is created, OABGen creates the OAB version 2, OAB version 3a, and OAB version 4 folders. You can specify the versions of OABs that are generated. [Exchange 2007]