Completing the Migration to Exchange Server 2003

When all Exchange 5.5 servers are no longer required, the organization can convert to Native Mode Exchange Server 2003. This section covers the steps that need to be accomplished before the conversion to Native Mode can be executed. This section also covers some of the post-migration clean-up processes that need to be run in the Exchange Server 2003 organization. Not all of the clean-up 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 provides the organization with the following benefits and flexibility:

• 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.

• SMTP becomes the default routing protocol.

There are very few reasons to keep an Exchange organization in Mixed Mode after all Exchange 5.5 servers have been removed. You should change your Exchange organization to Native Mode in the following scenarios:

• 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 futurethe 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 Server 2003, the following steps must be accomplished in the following order:

1. Delete all Directory Replication Connectors.

2. Delete all Exchange 5.5 servers from each remaining site.

3. Delete the recipient connection agreements and all other connection agreements for each Exchange 5.5 site.

4. Delete the Site Replication Service (SRS) from all Exchange Server 2003 systems.

5. Switch to Native Mode using the Change Mode button on the organization's properties.

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 Tools to view Site Replication Service. 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 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 the ADC

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 SRS

The Site Replication Services are the last services 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 Services 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:

1. Open the Exchange System Manager.

2. Right-click the organization and click Properties.

3. Click the General tab, and then click Change Mode under Change Operations Mode. Click Yes to permanently switch the organization's mode to Native Mode.

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 Post-Migration Clean-Up

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.

The most efficient method of migrating to Exchange Server 2003 is to migrate the Windows NT 4.0 user accounts to Active Directory before beginning the Exchange Server 2003 migration, either through an in-place upgrade of the Windows NT 4.0 Primary Domain Controller or by using a migration tool such as the Active Directory Migration Tool (ADMT) v2.0 or other third-party tool. This eliminates the need to run the ADClean utility because the ADC will automatically match the Active Directory account to the mailbox, as long as it's specified as the primary Windows NT account for the mailbox. The ADC will then add the attributes for the mailbox to the existing Active Directory user account.

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 due to 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.

TIP

The Search Based on Exchange Mailboxes Only option allows ADClean to search for only duplicate accounts created by the ADC.

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.