Decommissioning Exchange Legacy Servers

The final step is to decommission the Exchange 2000 or 2003 Server and we can consider the transition done. The Exchange 2003 server should be removed using the Exchange 2003 Setup program, which can be launched via Add or Remove Programs (Figure 3.12).

Figure 3.12: Add or Remove Programs

But before you begin uninstalling the Exchange 2003 Server, we first need to assign the Recipient Update Service (RUS) to our Exchange 2007 Server. Not because RUS should be used (in fact Exchange 2007 no longer uses RUS), but because the Exchange 2003 Setup program won’t let us uninstall Exchange 2003, before RUS has been assigned to another server. In order to assign RUS to the Exchange 2007 Server, open the Exchange 2003 System Manager, then expand the Recipients node and select Recipient Update Services. Now open the property page both for Recipient Update Service (Enterprise Configuration) and Recipient Update Service (domain), then click the Browse button under the Exchange Server text box and specify the Exchange 2007 Server instead, then click OK twice and close the System Manager as shown in Figure 3.13.

Note
It's important you don't delete the recipient policies in the Exchange 2003 System Manager, since Exchange 2007 uses them when provisioning users. 

Figure 3.13: Assigning the Recipient Update Service to the Exchange 2007 Server

Note:
Microsoft will release an Exchange 2003 hotfix, which will prevent one from reassigning the RUS to an Exchange 2007 server some time in the future. The reason being, this really is an invalid setting that should be blocked. Instead the recommendation will be to use ADSIedit to remove the enterprise RUS object.

Now we can continue uninstalling the server, so select Microsoft Exchange then click the Change/Remove button.

The Exchange 2000 or 2003 wizard will appear, click Next then select Remove in the Action dropdown box as shown in Figure 3.14. Click Next.

Note
If your organization relies heavily on Public Folders, you might want to leave the Exchange System Management Tools intact, as you can use them to administer Public folders on your Exchange 2007 server. Remember Exchange 2007 doesn't have a UI for Public Folder Management.

Figure 3.14: Exchange 2003 Installation Wizard Component Selection Page

On the Installation Summary page click Next and wait for the Exchange 2003 uninstallation process to complete (Figure 3.15).

Note
If the Exchange 2000 Setup files aren’t located on an accessible drive, network share, you will be prompted to insert the Exchange 2003 CD media during the uninstallation process.

Figure 3.15: Exchange 2003 Uninstallation Process

When the uninstallation process has completed click Finish to exit the Exchange 2003 Setup wizard (Figure 3.16).

Figure 3.16: Exchange 2003 Successfully Uninstalled

 Alright we’re done!

Note
If the Exchange 2003 uninstallation for some reason fails, it may be necessary to remove the Exchange 2003 Server by deleting the Server object in the Exchange System Manager or even via ADSIEdit if this isn’t possible. But please don't delete the respective legacy (Exchange 2003) Administrative Group, as the user's legacyDNs still points there, even though their mailboxes are being moved in a native organization. 

Conclusion

Doing a transition from an Exchange 2000 or 2003 Server to an Exchange 2007 in the same Active Directory Forest is a straightforward process, and since Exchange 2007 co-exists just fine with legacy Exchange servers, you can do the transition at your own pace. Co-existence support is laudable as a transition process typically happens in several phases. This is especially true if you’re going to do a transition from multiple legacy Exchange Servers to multiple Exchange 2007 Servers.

I like the fact that the Exchange 2007 Setup wizard knows when Exchange 2007 is deployed in an existing legacy Exchange organization, and in this case prompts you to create a routing group connector so that mail flow is established between the legacy routing group and the Exchange 2007 routing group. It’s also nice to see that Exchange 2007 Setup, in this case, creates a Public Folder database and automatically adds the Exchange 2007 Server to the OFFLINE ADDRESS BOOK and SCHEDULE+ FREE BUSY system folders replica lists, so you only have to concentrate on replicating Public Folders.

Finally it’s a real pleasure working with the Exchange 2007 Move Mailbox wizard (or Move-Mailbox cmdlet) in order to move legacy mailboxes to an Exchange 2007 Mailbox Server, but I must admit, support for Public Folder management in the Exchange 2007 Management Console GUI is missed.