This article describes how to convert a Microsoft Exchange 2000 organization or a Microsoft Exchange 2003 organization that is currently running in mixed mode to native mode. Follow these steps after the last Exchange 5.5 server in the organization is upgraded or before the last Exchange 5.5 server is decommissioned.
An organization running in native mode can accommodate only Exchange 2000 or Exchange 2003 computers. New Exchange Server 5.0 or 5.5 computers cannot be introduced into the organization.
You can switch an Exchange 2000 or Exchange 2003 organization to native mode after all of the servers in that organization are upgraded to Exchange 2000 or Exchange 2003. You cannot switch to native mode until you either upgrade or decommission all earlier versions of Exchange Server.
The following are some of the features of Exchange 2000 and Exchange 2003 native mode:
Support for multiple routing groups within a single administrative group.
Routing groups can consist of servers from multiple administrative groups.
Ability to move servers between routing groups.
Ability to move mailboxes between servers in different Administrative Groups within an organization.
Simple Mail Transfer Protocol (SMTP) is the default routing protocol.
An administrative group does not have to contain any routing groups and a server can belong to an administrative group without belonging to a routing group within that administrative group.
Before you can change an organization from mixed mode to native mode, all of the computers in the organization must be running Exchange 2000 or Exchange 2003. The switch to native mode cannot be reversed. Review the implications of this switch before proceeding.
After you upgrade or remove all versions of Exchange Server prior to Exchange 2000, you can switch your Exchange 2000 or Exchange 2003 organization to native mode by using Exchange System Manager:
Start Exchange System Manager. Click Start, point to Programs, point to Microsoft Exchange, and then click System Manager.
Right-click the organization, and then click Properties.
Click the General tab, and then click Change Mode under Change Operations Mode. Click Yes if you are sure that you want to permanently switch the organization's mode to native mode.