Configuring Message Routing

Adding Exchange 2000 Servers to Exchange 5.5 Sites

For maximum coexistence flexibility, you can install an Exchange 2000 server in an existing Exchange 5.x site. This feature allows organization with earlier versions of Exchange clients and servers to take advantage of new Exchange features without upgrading the entire installation. When adding an Exchange 2000 server to a mixed-mode topology, you need to create a new administrative group and join it to the Exchange 5.5 topology.

When Exchange 5.x servers and Exchange 2000 servers communicate within the same site, they use only remote procedure call (RPC). If two Exchange 2000 servers are present in a mixed-mode site, they communicate with each other using SMTP. The earlier versions of Exchange servers communicate with each other using RPC.

All intra-site directory replication between Exchange 5.x and Exchange 2000 occurs through the Active Directory Connector (ADC), rather than through normal RPC mechanisms. Through a connection agreement of the ADC, all gateways and connectors in the Exchange 5.x environment can be used by all versions of Exchange servers.