Migrating to Exchange Server 2007 : Moving to Native Mode in Exchange

For an organization that previously had Exchange Server 5.5 in their environment, or possibly still has Exchange 5.5 servers in the environment, before the migration to Exchange 2007 can begin, the organization must remove all Exchange 5.5 servers. In addition, the organization must decommission all remnants of Exchange 5.5, such as site connectors and Active Directory Connectors (ADCs), and switch the Exchange organization into Native mode before proceeding with the migration to Exchange 2007.

This section covers the steps that need to be accomplished before the conversion to Native mode can be completed. This section also covers some of the postmigration cleanup processes that need to be run in the existing Exchange 2000 or Exchange 2003 organization structure prior to migrating to Exchange 2007. Not all of the cleanup processes need to be run in all environments; this depends on the method the organization used to populate Active Directory.

Converting to Native Mode

Converting to Native mode changed the way that Exchange 2000 and Exchange 2003 operated that was slightly different from the way Exchange 5.5 worked. The functions in Native mode Exchange are similar to the way Exchange 2007 operates, so rather than having backward support to Exchange 5.5 functionality that is not supported in Exchange 2007, Microsoft requires Native mode as a prerequisite before the organization can migrate to Exchange 2007. The functions in Exchange Native mode are as follows:

• Multiple routing groups are supported.

• Routing groups can contain servers from different administrative groups.

• Servers can move between routing groups.

• Mailboxes can be moved between administrative groups.

• Simple Mail Transfer Protocol (SMTP) becomes the default routing protocol.

To shift the organization to Native mode, the following conditions must be met:

• No more Exchange 5.5 servers exist in the organization.

• No plans exist to add Exchange Server 5.5 servers to the organization in the future—the likelihood for a merger or acquisition is low.

• No need exists for connectors or gateways that run only on Exchange 5.5.

To convert to Native mode Exchange, the following steps must be accomplished in the following order:

Deleting All Directory Replication Connectors

For any remaining Exchange 5.5 site that will not be migrated to Exchange Server 2003, the directory replication connectors must be deleted.

Use the Exchange System Manager to delete all directory replication connectors. To delete the directory replication connectors, click to expand the Tools view to display the Site Replication Service objects in the Exchange organization. Click the View menu and select Directory Replication Connector View. Click each directory replication connector and press Delete.

Next force replication to propagate the deletion of the directory replication connectors in the Active Directory Connector Manager by using the Replicate Now option on the connection agreements for the site. Verify the deletion of the directory replication connectors by opening the Exchange System Manager on another Exchange Server 2003 system and viewing the Site Replication Service with the Directory Replication Connector view. When the directory replication connector no longer appears, the deletion has been replicated.

Removing All Exchange Server 5.5 Servers from the Organization

When all the Exchange 5.5 servers are no longer needed, they should be uninstalled through the Exchange 5.5 setup program. The last server to be uninstalled should be the server that was the first server in the site or that contains the first server in the site components.

After all the servers have been uninstalled, the last server must be deleted manually from the Exchange hierarchy. To delete the server from the hierarchy, use the Exchange 5.5 Administrator program to connect to the Exchange Server 2003 system running the Site Replication Service and locate the list of servers in the site. Click the server to be removed and then click Edit, Delete. A warning appears if the server still contains mailboxes or connectors. Click Yes to continue the deletion. Another warning appears if there are still public folder replicas on the server. Click Yes to continue the deletion.

The next step is to force replication through the ADC for all connection agreements for the site by using the Replicate Now option. Verify that the server has been removed from Active Directory through the ADC before deleting the connection agreements and uninstalling the ADC. The server should no longer appear in the Exchange System Manager.

Removing Active Director Connectors

Open the Active Directory Connector Manager and delete all connection agreements. If the connection agreements are not deleted, the membership of distribution groups could be lost.

If the Active Directory Connector is no longer needed and all connection agreements have been removed, uninstall the Active Directory Connector through Control Panel, Add/Remove Programs. Also remember to disable or delete the service account used for the ADC if it’s not used for any other services.

Deleting the Site Replication Service

The Site Replication Service is the last service to be deleted before the conversion to Native mode can take place. To delete the Site Replication Service, open the Exchange System Manager, and expand the Tools icon. Next expand the Site Replication Service icon, and then right-click each Site Replication Service and click Delete.

Throwing the Native Mode Switch

After the conversion to Native mode, there is no way to return to Mixed mode. The organization should be completely confident about the transition. When all the prerequisite steps have been accomplished, the Change Mode button on the organization properties in the Exchange System Manager should be available. Use the following steps to convert to Native mode Exchange Server 2003:

After the conversion to Exchange Server 2003 Native mode, administrative groups are always displayed in the organization. Administrators have the choice of disabling the display of routing groups.

Performing Postmigration Cleanup

Depending on the method that was used to populate the Active Directory, the organization might have to use a utility called ADClean that merges duplicate Active Directory accounts created during the migration process to Exchange Server 2003. If the Active Directory Connector was used to populate the Active Directory from the Exchange 5.5 directory before the Windows NT 4.0 domain accounts were migrated to Active Directory, two entries will exist for each user. The two user account entries should be merged through ADClean to complete the migration and clean up Active Directory.

Duplicate accounts in Active Directory can also occur if two ADC recipient connection agreements were created and marked as primary on a particular container. One account displays as disabled with a red x in the user icon and with a –1 appended to the display name. The other account displays normally. ADClean can also be used to merge these accounts. To merge accounts created because of duplicate connection agreements, run ADClean and select the container to search. On the next screen, verify the accounts to merge and then choose the option to begin the merge or export the merge to a file for import through ADClean later.

The ADClean utility is installed during setup in the \exchsrvr\bin directory. ADClean gives administrators the capability to manually select accounts to be merged or run the wizard to search for and suggest accounts to be merged. The merge can be executed immediately or exported to a .csv file to be reviewed by the administrator and then executed later through ADClean.