How to Remove the Last Exchange 5.5 Server

Migrating to Exchange 2000 native mode

As organizations upgrade their Exchange Server 5.5 infrastructures to Exchange 2000 Server, they need to remove and upgrade Exchange 5.5 servers. Deleting the server from the organization means removing the Exchange 5.5 server's directory entries that a mixed-mode Exchange 2000 administrative group includes in both the Exchange 5.5 directory and Active Directory (AD). However, you need to avoid some pitfalls in the process.

The lessons I learned from deleting the last Exchange 5.5 server in an administrative group in my company's Exchange organization will be useful to administrators involved in planning and performing migrations to Exchange 2000. "Related Reading," page 6, lists Microsoft articles that provide more detailed information about some of the steps.

In my organization, three servers were in the administrative group NSIS European Messaging Team: DBOIST-MSXCL (running Exchange 5.5), DBOEXCVS1 (running Exchange 2000), and VBEEXCPS01 (running Exchange 2000 with Site Replication Service—SRS). My objective was to remove DBOIST-MSXCL from the administrative group with minimum disruption to service.

Action Plan
Before you begin deactivating the server, you need an action plan. The action plan includes who's responsible for moving each component and the order in which the changes should occur. An action plan for removing the last Exchange 5.5 server should include the following steps:

To understand what these steps entail, let's look more closely at each step.

Back Up the Server
Back up the Directory Store and the Information Store (IS) on the server you're removing. Retiring a server makes many changes to your Exchange configuration. For example, you might rehome public folders, change messaging-connector settings, and remove mailboxes from the server. Taking a full backup at this stage gives you a back-out option in case anything goes wrong. Store the backup tape in a safe place.

Survey the Server's Configuration
To be sure that you account for all the decommissioned server's functions, you need to know what roles the server performs. For example, a server might not host active user mailboxes, but it might host critical public folders such as the site's Schedule+ Free/Busy folder. Document how the server is configured, including the following components:

The Exchange 5.5 server I was decommissioning had been my group's production Exchange server for several years. The server hosted mailboxes, public folders, DRCs, X.400 connectors, and an Internet Mail Service (IMS) connector. Over the past year, I transferred user mailboxes and these server roles to a new Exchange 2000 server.

If you can, remove the server over a few days to let the transfer of server roles take place with the lowest risk. Let replication finish after each change to facilitate assessing the impact of each change. Performing all the changes at the same time can lead to problems such as incomplete transfer of roles, stranded public folders, and incomplete directory replication.

Move the Messaging Connectors
Transfer any messaging bridgehead connections from the server to an Exchange 2000 server in the site. My company runs a hub-and-spoke Exchange messaging architecture. All intersite messaging traffic for the administrative group travels over an X.400 connector to a central hub site. The messaging team created a new X.400 connector to the hub site on one of the Exchange 2000 servers and deleted the X.400 connector on the Exchange 5.5 server.

Remember that when you use X.400 connectors to connect sites, you need to set up the configuration address space in both sites. The X.400 address space is composed of country/region name, Administrative Management Domain (ADMD) name, private management domain name (p), organization name (o), and organizational unit (OU). To configure the address space, use the Microsoft Exchange Administrator program and go to the Connected Sites tab of the X.400 connector's Properties dialog box.

Exchange 2000 supports all the Exchange 5.5 connectors (e.g., Microsoft Mail—MS Mail, Lotus Notes, Novell GroupWise), so you can create them on Exchange 2000 servers. To minimize the impact of the transition, make changes to messaging connectors outside business hours. Test outbound delivery by sending messages to mailboxes in servers in other sites and request delivery receipts. Check Internet message connectivity by sending messages to your Exchange mailbox from a free email service such as Microsoft Hotmail.

Move the DRCs
In a mixed-mode site, the SRS server replicates configuration information between the Exchange 5.5 directory and AD. Transfer the directory replication bridgehead role from the server you're deleting to the SRS server. The SRS is on the first Exchange 2000 server that joins a site. You can't move the SRS from one server to another, but you can recreate it on another server in the site. The Microsoft article "XADM: How to Create an Additional Site Replication Service for a Mixed Site" (http://support.microsoft.com/default.aspx?scid=kb;en-us;q255285) explains how to recreate the SRS. Note that you can't locate the SRS on a cluster.

Rehome the Public Folders
Use Exchange Administrator to check which public folders are homed on or replicated to your server by looking under public information storepublic folder resources, which Figure 1 shows. For more detailed information about public folders (e.g., replicas, permissions), use the pfadmin.exe and pfinfo .exe utilities. Pfadmin is part of the Microsoft BackOffice Resource Kit (BORK), and you can obtain Pfinfo from Microsoft Product Support Services (PSS). The procedures for using these utilities are documented in the Microsoft article "XADM: Readme Document for the Pfinfo.exe Program" (http://support.microsoft.com/default.aspx?scid=kb;en-us;q261093).

Rehome any public folders that are homed on the server you're deleting. Go to the Advanced tab of the public folder's Properties dialog box, which Figure 2 shows, and choose the new server from the drop-down menu.

Delete or Move User Mailboxes
Although deleting or moving mailboxes might seem obvious, be sure to double-check that no active mailboxes remain on the server. Some time might have passed since you moved the mailboxes off the server, and an administrator might have created new mailboxes since that time.

Also, check that no hidden mailboxes are on the server. You can see whether mailboxes are hidden by going to View, Hidden Recipients in Exchange Administrator. Delete or move the mailboxes from the server. Although you can obtain a list of hidden mailboxes by executing a Lightweight Directory Access Protocol (LDAP) query from the Microsoft Management Console (MMC) Active Directory Users and Computers snap-in, you can delete the mailboxes only from Exchange Administrator.

Delete or Move Application or Service Mailboxes
Many Exchange add-on products use a mailbox to log on to the mail store. My company's server had several mailboxes for applications such as Sybari Software's Antigen. Verify that you can shut down the applications and delete their mailboxes. If you can't delete a mailbox, move it to an Exchange 2000 server. You might need to update the application that uses the mailbox so that it can use the modified mailbox.

Check the Site Folders
Exchange uses several hidden system public folders called the site folders. The site folders are

The Exchange Setup program creates these folders on the first server in a site at installation. Although the server you're removing might not have been the first server in the site, an administrator might have transferred the site folders to this server because someone subsequently removed the original first server in the site. You can view site folders through Exchange Administrator under Folders, System Folders.

OAB. Exchange 2000 users must use an OAB that Exchange 2000 generates. Verify that Exchange 2000 has generated an Offline Address List by using Exchange System Manager (ESM) to check the Mailbox Store's Properties, as Figure 3 shows. Then, use Exchange Administrator to delete the Exchange 5.5 OAB. In Exchange Administrator, navigate from Site, Configuration, DS Site Configuration to the Properties dialog box, go to the Offline Address Book tab, which Figure 4, page 4, shows, then click Remove.

Schedule+ Free/Busy public folder. Ensure that you've rehomed the Schedule+ Free/Busy folder for your Exchange site from the Exchange 5.5 server to an Exchange 2000 server in the site. To rehome the folder, use Exchange Administrator to navigate to Folders, System Folders, SCHEDULE+ FREE BUSY. The General tab of the folder's Properties dialog box shows the name of the public folder's home server, as Figure 5, page 4, shows. If the home server name lists the server you are deleting, click the Advanced tab and use the drop-down menu to rehome the Schedule+ Free/Busy folder to an Exchange 2000 server in the site. These steps are similar to the public folders rehoming procedures.

In ESM, you can check whether the Free/Busy folder has been rehomed by navigating to Public Folder Store, Storage Group, Public Folder Store, Public Folder Instance. Right-click the Schedule+ Free/Busy folder, and select Folder Properties, which Figure 6 shows.

Organization forms. Rehome any organization forms on the server. In Exchange Administrator, navigate to Folders, System Folders, EForms Registry, Organization Forms. Check the properties on the Organization Forms public folder. Rehome the public folder as before by using the drop-down menu on the Advanced Properties tab to select an Exchange 2000 server in the site.

If you've deleted the first server in the site before reassigning the site folders, don't panic. You can recreate them in Exchange 2000 with the guiden.exe utility, which the Microsoft article "XADM: How to Reset System Folders on an Exchange 2000 Server" (http:// support.microsoft.com/default.aspx?scid=kb;en-us;q275171) documents. You can obtain guiden.exe from the Microsoft Developer Network (MSDN) or Microsoft PSS.

Uninstall the Exchange Event Service
Developers use the Exchange Event Service to process events in workflow applications. A server running the Event Service has a system public folder under Folders, System Folders, Events Root. To prevent this public folder from being orphaned, run the Exchange 5.5 Setup program on the server you're deleting and remove the Event Service component.

Check the Routing Calculation Server
The first server in a site has the role of routing calculation server. The routing calculation server generates the Exchange 5.5 Gateway Address Routing Table (GWART). In a mixed-mode site, the SRS assumes this role. Use Exchange Administrator to verify that the SRS server has assumed the role by navigating to the Site Addressing properties for your site, under the Site, Configuration container. In Figure 7, the General tab of the Site Addressing dialog box shows that VBEEXCPS01 is the routing calculation server for the site; VBEEXCPS01 is also the SRS server.

Update the ADC CAs
Ensure that no CAs are configured to use the server you're about to delete. Redirect the CAs to the SRS server for your site.

Check the DLs' Expansion Servers
Ensure that no DLs have listed the server you're deleting as an expansion server. To obtain a list of expansion servers, you need to export DL information to a Comma Separated Value (CSV) file by clicking Tools, Directory Export and selecting the Distribution list check box, as Figure 8 shows. Expansion servers appear under the Home Server column of the CSV file. Be sure to perform the export for all recipient containers in your site. You can also use Directory Export to generate a list of hidden recipients. If someone sends a message to a DL for which you've deleted the expansion server, Exchange won't deliver the message because it won't be able to find the expansion server.

Back Up the Server Again
After you've made all the changes, take the precaution of taking another full backup of the Exchange Directory and mail stores. Keep this second backup tape in a safe place.

Power Down the Server
At this point, you've moved all the connectors off the server, moved the mailboxes, updated all the public folders, and let replication finish. Before you finally delete the server, however, Microsoft recommends that you power down the server for a day or two. While the server is down, perform these tests.

These tests will help verify that you've correctly followed the procedures to prepare the server for deletion.

Delete the Server
After you complete this preparation, you're ready to delete the server from your organization. Follow these preliminary steps.

The Administrator program removes the Exchange 5.5 server from the SRS database. The Config_CA object processes this deletion, then replicates it to AD.

As long as you have Exchange 5.5 servers in your Exchange organization, you need to run an SRS in your administrative group. The SRS acts as a shadow Exchange 5.5 directory while Exchange is running in mixed mode.

Remove the last Exchange 5.5 server in the organization by performing the following tasks. Note that you should take these actions only when you're deleting the last Exchange 5.5 server in an Exchange organization. The Microsoft article "XADM: Preparing a Mixed Mode Organization for Conversion to Native Mode" (http://support.microsoft.com/default.aspx?scid=kb;en-us; q272314) gives more detail about this process.

When this procedure is complete, you can switch from mixed to native mode. To change the mode, open ESM. On the General tab of the Exchange organization's Properties dialog box, click Change Mode. Note that this process is a one-way operation; after you convert an organization to native mode, you can't set it back to mixed mode.

The Change Mode button will be disabled as long as Exchange 5.5 servers remain in the organization. If the Change Mode option is still disabled after you've removed all Exchange 5.5 servers, use ESM to check that no instances of the SRS remain. (Look under Tools, Site Replication Services.) Exchange doesn't automatically remove all SRS instances when you remove or upgrade Exchange 5.5 servers.

Disable the Service Account
After you retire the Exchange 5.5 servers, don't forget to delete the Exchange service account. This account has logon as service rights and Domain Administrator privileges. Domain Administrator rights are the most powerful privileges in a Windows NT 4.0 domain. A domain administrator can manage accounts, change passwords, take ownership of all files, and perform other tasks, so you should carefully control membership in the Domain Administrator global group. Make sure other applications aren't using the account. As a precaution, disable the account first for a few days before deleting it.

Update Your Documentation
Don't forget to update your documentation to reflect the changes you've made to your Exchange infrastructure. You might have transferred messaging connectors from your Exchange 5.5 servers to your Exchange 2000 servers. If you have a multi-tiered support organization, communicate the changes to the relevant people. Update your disaster-recovery procedures and server-build procedures, if necessary, and change any references to the server you removed.

Redeploy the Hardware
Think about how you can redeploy the server you've uninstalled from Exchange. My server was about 5 years old, and the hardware specification wasn't on the Windows 2000 Hardware Compatibility List (HCL). My company has redeployed legacy Exchange servers as Instant Messaging (IM) servers. IM imposes a light server load, so older servers can handle it. Or you might decide to reuse the hardware for testing.

Plan Carefully
Phasing out Exchange 5.5 servers from your organization requires careful planning and implementation. I've described the basic steps. The Microsoft articles in "Related Reading" will help you with the details. When the migration is complete, you can take advantage of all the benefits of managing Exchange 2000 in native mode.