A. Microsoft provides the InterOrg Replication Tool to synchronize public folders and free/busy information between Exchange organizations running Exchange 2000 Server Service Pack 3 (SP3) or later. The tool consists of two components:
- The Replication Configuration program (exscfg.exe)
- Replication service (exssrv.exe)
All communication is via RPC (port 135) and two randomly picked ports (unless you configure fixed RPC ports), so make sure that any firewalls between the Exchange servers allow RPC communication.