Upgrading from Exchange 2000 Server to Exchange Server 2003

Exchange 2000 Server will always be running on Windows 2000 Server and not on Windows Server 2003. This is because Exchange 2000 Server cannot run on the Windows Server 2003 platform. Exchange 2000 Server will either be in a Windows 2000 environment or on a Windows 2000 member server in a Windows Server 2003 environment. This is because Exchange 2000 Server, like Exchange Server 2003, requires Active Directory to function correctly.

There are several platform requirements that must be met before Exchange 2000 Server can be upgraded to Exchange Server 2003. These requirements are as follows:

• Domain controllers must be running Windows 2000 Service Pack 3 or Windows Server 2003 If the domain in which Exchange 2000 servers are to be upgraded to Exchange Server 2003 has Windows 2000 domain controllers, these domain controllers must be patched to at least Service Pack 3. If the domain in which the Exchange 2000 servers that are to be upgraded to Exchange Server 2003 has Windows Server 2003 domain controllers, no further patching is required.

• Global catalog servers must be running Windows 2000 Service Pack 3 or Windows Server 2003 Similar to the preceding requirement, to support Exchange Server 2003, global catalog servers must be running Service Pack 3 or higher. Alternatively, if global catalog servers are running Windows Server 2003, no further patching is required.

• It is recommended that you have a global catalog server in each domain in which Windows Server 2003 is installed This facilitates the generation of distribution lists for other domains within the forest. If global catalog servers are not installed, the generation of these distribution lists can take much longer.

• The computers that will be hosting the upgraded Exchange Server 2003 must be running Windows 2000 Service Pack 3 (or higher) As Exchange 2000 Server cannot run on Windows Server 2003, any upgrade of the host computer to this operating system must occur after Exchange Server has been upgraded. Always upgrade Exchange 2000 to Exchange Server 2003 BEFORE upgrading Windows 2000 Server to Windows Server 2003.

• A Windows 2000 cluster running Exchange is patched to Service Pack 4 If Exchange 2000 Server is running on a cluster of Windows 2000, Windows 2000 must be patched to Service Pack 4. This is required to support Kerberos authentication within the Exchange cluster.

After the necessary upgrades have been made to the platform on which Exchange Server 2003 will run, Exchange 2000 Server needs to be upgraded.

Preparing Exchange 2000 Server for Upgrade to Exchange Server 2003

Upgrading Exchange 2000 Server to Exchange Server 2003 requires that the Exchange 2000 server undergo some preparation. The following conditions need to be met:

• Exchange 2000 Server must have the Exchange 2000 Service Pack 3 applied before being upgraded to Exchange Server 2003 Problems will arise if an attempt is made to upgrade a version of Exchange 2000 Server to Exchange Server 2003 prior to the application of Service Pack 3.

• All Exchange 2000 databases are backed up before the upgrade occurs This way, if something goes wrong, you can always roll the upgrade back.

• The components that are unsupported by Exchange Server 2003 are uninstalled before the upgrade takes place These components are listed in Table 3.1. To remove these components, use Exchange 2000 setup. If you require these components for your organization, do not upgrade the servers on which they are installed. Install Exchange Server 2003 on other servers within the organization and have them coexist with the Exchange 2000 servers. In some cases, the functionality of these components is built into the Exchange Server 2003 core.

Table 3.1. Exchange 2000 Server Components Unsupported by Exchange Server 2003

Component	Description
Microsoft Mobile Information Server	Supports mobile devices such as PocketPC
Instant messaging service	Supports the instant messaging client
Exchange Chat service	Supports chat rooms
Exchange 2000 Conferencing Server	Allows data conferencing as well as audio and video conferencing
Key Management Service	Interfaces with organizational certificate authority
cc: Mail connector	Connects Exchange to cc: Mail
MS Mail connector	Connects Exchange with MS Mail

If the Exchange 2000 server has been extensively tuned to maximize performance, you might also need to roll back these alterations. Either the performance enhancements are no longer applicable to Exchange Server 2003 or the performance enhancements themselves might cause problems on the new platform.

When planning an upgrade of Exchange 2000 Server to Exchange Server 2003, the current state of POP3, IMAP4, and NNTP services are preserved. Any special configuration changes that have been made are carried over to the new installation.

Preparing the Domain for the Upgrade to Exchange Server 2003

Although you ran Exchange 2000 ForestPrep and DomainPrep when setting up Exchange 2000 Server, you must rerun the Exchange Server 2003 versions of these utilities before upgrading to Exchange Server 2003. As was the process with installing Exchange 2000 Server, ForestPrep must be run first. It is important to note that if Schema Manager was used to index Exchange Server 2000 schema attributes, you will be required to verify and reapply all manual changes that were made to the original schema after ForestPrep finishes upgrading. Exchange Server 2003 ForestPrep does not preserve custom changes made to Exchange 2000 Server schema, starting fresh with its own Exchange Server 2003 schema.

Unfortunately, there is one large bug in the upgrade process to Exchange Server 2003 in a Windows 2000 AD environment that has a preexisting Exchange 2000 infrastructure. The InetOrg schema entries are incorrect and you must apply a script to modify these entries before running Exchange 2003 ForestPrep. For more information, consult Microsoft Technet. The relevant article is Q314649.

After Exchange Server 2003 ForestPrep has been run, the Exchange Server 2003 version of DomainPrep must be run as well. DomainPrep does not need to be run in every domain in the forest, but it does need to be run in the following locations:

• The root domain of the Active Directory forest

• Any domain in the forest that will host an Exchange 2003 server

• Any domain in the forest that will host Exchange Server 2003 mailbox-enabled objects, regardless of whether Exchange Server 2003 will be installed in that domain

• Any domain that contains users and groups that will manage the Exchange Server 2003 organization

After these steps have been taken, Exchange Server 2003 can be installed on the same server as Exchange 2000 Server. The process is essentially the same as that which is detailed in Chapter 1, "Microsoft Certification Exams." The Exchange Deployment Tools will guide you through the process. As many things, such as the Exchange organization name, will already have been configured during the installation of Exchange 2000 Server, there are fewer questions to answer during the upgrade process.

Upgrading Front-end and Back-end Servers

Special steps are required if you are migrating an organization that uses Exchange 2000 Server in a front-end/back-end configuration. Front-end/back-end configuration is often used with systems like Outlook Web Access on a network demilitarized zone (DMZ), or screened subnet. If the current Exchange 2000 organization uses a front-end/back-end architecture, the upgrade must be planned so that the front-end servers are all upgraded before the back-end servers. This process can be seen in Figure 3.1. An Exchange Server 2003 front-end server can support both an Exchange 2000 server or an Exchange Server 2003 system configured as the back-end server. An Exchange 2000 front-end server cannot support an Exchange Server 2003 back-end server. More about Exchange in front-end/back-end configuration can be found in Chapter 6, "Managing, Monitoring, and Troubleshooting the Exchange Organization."

Figure 3.1. Upgrade the front-end server to Exchange Server 2003 before upgrading the back-end server to Exchange Server 2003.