Microsoft Exchange Server 2003 Deployment Guide- P31 doc

301 Switching from Mixed Mode to Native Mode Because Exchange 2000 Server and Exchange Server 2003 are structured to take advantage of Active Directory functionality, there are some limitations when Exchange Server 2003 coexists in the same organization with Exchange Server 5.5. When Exchange 2000 Server or Exchange Server 2003 servers coexist with Exchange Server 5.5, your organization must run in mixed mode. Running in mixed mode limits the functionality of Exchange Server 2003. Therefore, after migrating from Exchange Server 5.5 to Exchange Server 2003, it is recommended that you switch from mixed mode to native mode. This section discusses the advantages of a native-mode Exchange organization and provides the steps that are necessary to switch from mixed mode to native mode. You are ready to change your Exchange Server 2003 organization to native mode if:  Your organization will never require interoperability between your Exchange Server 2003 servers and Exchange Server 5.5 servers in the same organization. 302  Your Exchange Server 5.5 servers exist in an organization that is separate from your Exchange Server 2003 servers. Note: After you switch your Exchange Server 2003 organization from mixed mode to native mode, you cannot switch the organization back to mixed mode. Make sure that your Exchange Server 2003 organization will not have to interoperate with Exchange Server 5.5 in the future before you switch from mixed mode to native mode. First, however, you should determine in which mode your Exchange organization is currently running. For detailed steps, see How to Determine if You Are Running Exchange in Mixed or Native Mode. Exchange Server 2003 Considerations for Mixed and Native Mode As mentioned earlier, after you migrate from Exchange Server 5.5 to Exchange Server 2003, by default, your organization runs in mixed mode. Running Exchange Server 2003 in mixed mode has the following disadvantages:  Exchange Server 5.5 sites are mapped directly to administrative groups. 303  Administrative groups are mapped directly to Exchange Server 5.5 sites.  Routing group membership consists only of servers that are installed in the administrative groups.  You cannot move Exchange Server 2003 servers between routing groups.  Because many Exchange Server 2003 features are available only when you run your Exchange Server 2003 organization in native mode, it is recommended that you switch from mixed mode to native mode. Running Exchange Server 2003 in native mode has the following advantages:  You can create query-based distribution groups. A query-based distribution group provides the same functionality as a standard distribution group. However, instead of specifying static user memberships, with a query-based distribution group you can use an LDAP query to build membership in the distribution group dynamically. For more information about query-based distribution groups, see "Managing Recipients and Recipient Policies" in the Exchange Server 2003 Administration Guide. 304  Your routing bridgehead server pairs use 8BITMIME data transfers instead of converting down to 7-bit. This equates to a considerable bandwidth saving over routing group connectors.  The Exchange store in Exchange Server 2003 ignores and removes zombie access control entries (ACEs) from the previous Exchange Server 5.5 servers in your organization automatically. These zombie access control entries are security identifiers from previous Exchange Server 5.5 servers that have been removed from your organization.  Routing groups can consist of servers from multiple administrative groups.  You can move Exchange Server 2003 servers between routing groups.  You can move mailboxes between administrative groups.  Simple Mail Transfer Protocol (SMTP) is the default routing protocol. Removing Exchange Server 5.5 Servers Before you can switch from mixed mode to native mode, you must remove all Exchange Server 5.5 servers in your organization. This 305 section guides you through the process of removing the Exchange Server 5.5 servers from your organization. Removing an Exchange Server 5.5 Server Before you remove an Exchange Server 5.5 server from your site, verify that there are no mail connectors on the server. If there are, open a connector on another server in the site, and then verify mail flow. Next, remove the connectors on the server to be deleted. Retest message flow. For more information about removing your Exchange Server 5.5 connectors, see the Exchange Server 5.5 Help. For detailed steps about how to remove Exchange Server 5.5 servers, see How to Remove Exchange 5.5 Servers from Your Exchange 2003 Organization. Note: Ensure that the account to which you are logged on has Exchange Full Administrator permissions, as well as Exchange Server 5.5 service account administrator permissions for the site. 306 Important: If this is the first server in the site to be removed, see Microsoft Knowledge Base article 152959, "XADM: How to Remove the First Exchange Server in a Site" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=152959). Removing the Last Exchange Server 5.5 Server Before you can switch from mixed mode to native mode, you must remove all Exchange Server 5.5 servers in your organization. This section guides you through the process of removing the last Exchange Server 5.5 server from your organization. For detailed steps, see How to Remove the Last Exchange 5.5 Server from Your Exchange 2003 Organization. Removing Site Replication Service Site Replication Service (SRS) is a component that exchanges configuration information between Active Directory and the directory in Exchange Server 5.5. In Exchange Server 5.5, SRS is necessary because Exchange Server 5.5 configuration information can only be exchanged between Exchange Server 5.5 servers and Exchange 307 Server 5.5 directories—not with Active Directory. SRS mimics an Exchange Server 5.5 directory so that other Exchange Server 5.5 servers can replicate information to it. Using the configuration connection agreement created by Exchange Setup, Active Directory Connector replicates the configuration information in SRS into Active Directory. SRS runs only in a mixed-mode Exchange administrative group. SRS also performs additional functions, such as detecting and reacting to directory replication topology changes. You cannot switch from mixed mode to native mode until you have removed all instances of SRS. SRS is enabled automatically in two situations:  On the first Exchange 2000 Server or Exchange Server 2003 computer that you install in an Exchange site that is running only Exchange Server 5.5 servers.  When you in-place upgrade to Exchange 2000 Server from an Exchange Server 5.5 server that is the directory replication bridgehead server for a site. For detailed steps about how to remove Site Replication Service, see How to Remove Exchange SRS. After you complete these steps, you can convert the Exchange organization to native mode. 308 Switching to Native Mode For detailed steps about how to switch from mixed mode to native mode, see How to Convert from Mixed Mode to Native Mode in Exchange. After you switch your Exchange Server 2003 organization from mixed mode to native mode, you cannot switch the organization back to mixed mode. Before you perform the following procedure, make sure that your Exchange Server 2003 organization will not have to interoperate with Exchange Server 5.5 in the future. To take full advantage of Exchange native mode, you must restart the Microsoft Exchange Information Store service on all of the Exchange servers in your organization. You do not need to restart all of the Microsoft Exchange Information Store services simultaneously, but you must restart the service on each server for the server to take advantage of all Exchange native mode features. Restart the service on your servers after the change to native mode has been replicated to your local Windows domain controller. For detailed steps about how to restart the Microsoft Exchange Information Store service, see How to Restart the Microsoft Exchange Information Store Service. 309 Note: In the <Organization Name> Properties dialog box, the Change Mode button is unavailable if any Exchange Server 5.5 servers are present or SRS exists in the organization. Uninstalling Exchange Server 2003 After ensuring that your organization meets certain prerequisites, you can run Exchange Setup to uninstall Exchange Server 2003. For detailed steps, see How to Uninstall Exchange Server 2003. How to Upgrade the Exchange 2000 Active Directory Connector Before you can upgrade a server running Exchange 2000 Active Directory Connector to Exchange Server 2003, you must first upgrade the Exchange 2000 version of Active Directory Connector to Exchange Server 2003. 310 Procedure To upgrade an Exchange 2000 Active Directory Connector 1. On the server running the Exchange 2000 Active Directory Connector, click Start, click Run, and then type E:\adc\i386\setup.exe, where E is your CD-ROM drive. 2. On the Welcome to the Active Directory Connector Installation Wizard page, click Next. 3. On the Previous Installation Detected page, click Reinstall to upgrade your Exchange 2000 ADC to the Exchange 2003 ADC. The Previous Installation Detected page . Exchange Server 2003 servers and Exchange Server 5.5 servers in the same organization. 302  Your Exchange Server 5.5 servers exist in an organization that is separate from your Exchange. Exchange 2000 Server or Exchange Server 2003 computer that you install in an Exchange site that is running only Exchange Server 5.5 servers.  When you in-place upgrade to Exchange 2000 Server. from Exchange Server 5.5 to Exchange Server 2003, by default, your organization runs in mixed mode. Running Exchange Server 2003 in mixed mode has the following disadvantages:  Exchange Server