Exchange 2003 will prove to be a compelling upgrade for many organizations that are currently running Windows 2000/Exchange 2000 to support their messaging infrastructures. However, many of these same organizations will be loathe to migrate to Windows Server 2003 until it has at least one service pack under its belt and has proven itself. For these companies, Exchange 2003 can run on Windows 2000 Server, but with reduced functionality. Here are some of the pros and cons of running Exchange 2003 on Windows 2000, plus the details of how to carry out an installation.

Author’s note

At the time of this article, Exchange Server 2003 wasn’t shipping. For all of the examples below, I’ll be using Windows 2000 SP3 and Exchange Server 2003 Beta 2. I’ll be installing two Exchange 2003 systems for this article. The first one is a new installation onto a Windows 2000 SP3 system, and the second is an upgrade of an Exchange 2000 SP3 system. Both servers are in separate domains and are DNS, Active Directory, and Global Catalog servers for them.

Costs and benefits
In this case, the price that you’ll pay for installing Exchange 2003 on Windows 2000 is the loss of a number of the key benefits of moving to Exchange 2003 in the first place. Among these costs are the losses of:

  • RPC over HTTP: RPC over HTTP is not a function of Exchange server, but is instead included with IIS 6 running under Windows Server 2003. RPC over HTTP allows an Outlook 11 client to connect directly to the Exchange information store from outside the corporate firewall without the need for a full VPN. IIS 5 under Windows 2000 does not support this feature for Exchange.
  • Online backups: Users running Exchange 2003 under Windows Server 2003 will be able to take advantage of online snapshots of the information store by using the Volume Shadow Copy service. This service allows for an instantaneous backup and restore of the information store while still online. This removes a primary availability issue from previous versions of Exchange by keeping the information store available constantly and allowing for on-the-fly backups. Windows 2000 doesn’t support the Volume Shadow Copy service.

Probably the primary benefit of installing Exchange 2003 onto a Windows 2000 Server is that the impact of introducing a single new service—Exchange 2003—to your infrastructure will be much less than introducing more than one—Exchange 2003 plus Windows Server 2003.

Furthermore, if you don’t plan to install Exchange 2003 on new hardware but would rather upgrade your existing Exchange 2000 installation, you’ll have to upgrade it in place while still running Windows 2000, because Exchange 2000 will not run under Windows Server 2003. After Exchange is upgraded, you can later upgrade the server to Windows Server 2003.

System requirements
Running Exchange 2003 on Windows 2000 has system requirements that must be met before attempting the installation. First, Service Pack 3 (SP3) for Windows 2000 must be installed on the Exchange server as well as any global catalogs or domain controllers that Exchange will use. Second, there are other software requirements, including the SMTP and NNTP components from IIS, both of which must be installed on the Exchange server. If you’re already running Exchange 2000 on the system, these software components will already be installed.

Before upgrading an Exchange 2000 server, be aware that Exchange 2003 removes certain functionality from the product. I’ll discuss this more later.

Demonstration 1: A new installation of Exchange 2003 on Windows 2000
This scenario will likely be fairly uncommon, since Windows Server 2003 is shipping well before Exchange 2003 and organizations that have to add a new Exchange server should just install it under that operating system. However, some companies are much more wary about new operating system environments and will choose to deploy Exchange 2003 on Windows 2000.

Before you begin this installation, make sure that the Windows 2000 server you choose for installation meets the requirements explained earlier. Furthermore, make sure that your DNS servers have the appropriate records for your new mail server. Since I’m installing this demonstration server in my lab, it will be running on Windows 2000 SP3 with SMTP and NNTP enabled. The server is also an Active Directory domain controller and runs DNS services.

The installation
Installation begins by putting in the Exchange 2003 CD to start up the Exchange Server installation menu, as shown in Figure A. From the menu, choose Exchange Server Setup to start the installation. If you have autorun disabled on your CD-ROM drive, you can start the installer by running setup.hta from the root of the Exchange 2003 CD.

Figure A
Start from the Exchange Server installation menu.

For this example installation, I’m going to install Exchange 2003 and the System Management Tools onto the C: drive of my lab server, as shown in Figure B.

Figure B
This is a default Exchange Server 2003 installation.

If you don’t have an Exchange Organization yet, you’ll need to create a new one, as shown in Figure C. In this example, I’ll name it E2K3 (see Figure D). If you’re running Exchange 5.5, you could also join this Exchange 2003 server to that domain to migrate resources; however, doing so is beyond the scope of this article.

Figure C
Create a new Exchange Organization if you don’t have one yet.

Figure D
The Organization Name for this example is E2K3.

After these steps, you’ll be asked to agree to the terms and conditions of the product, and you’ll also be provided with a summary of the selections made. After these two steps, the Exchange 2003 installation will commence.

During this installation, the target domain’s schema is extended to support the additional attributes required by Exchange. If you would rather install Exchange in small bites rather than all at once, you can perform these extensions before installing the entire product by running the Setup.exe application from the \setup\i386 folder with the /forestprep and /domainprep switches.

Demonstration 2: An in-place upgrade of an Exchange 2000 server to Exchange 2003
Performing an in-place upgrade of Exchange 2000 to Exchange 2003 on Windows 2000 SP3 proves to be very simple once you’re beyond addressing the prerequisites.

Make sure that certain Windows 2000 servers are upgraded to Service Pack 3. These servers include any domain controller and global catalog servers that Exchange 2003 will use, in addition to the Exchange server itself.

Second, make sure that Exchange SP3 or higher is applied to all Exchange servers that you wish to upgrade. If you don’t perform this step, the Exchange 2003 installer will not run.

Since this demonstration presumes that you’re already running an Exchange 2000 system, your server should already have the SMTP and NNTP components installed, communication with the domain established, and DNS configured properly.

If your Exchange 2000 installation is itself an upgrade from Exchange 5.5, I highly recommend new hardware for the Exchange 2003 installation. While keeping hardware static can provide a savings, if there are difficulties in the process, the fact that multiple upgrades have been done on the system can make it much more difficult to track down the cause of problems.

Reduced functionality
Before upgrading Exchange 2000 to Exchange 2003, be aware that Exchange 2003 is missing some features that are present in Exchange 2000. Before upgrading to Exchange 2003, you must remove the unsupported features—Instant Messaging, Chat, and Key Management Service—from your Exchange 2000 installation.

For the same reason, these Exchange 2000 features cannot be administered using the System Manager from Exchange 2003. Moreover, these features cannot be enabled on a per-user basis on a server running Exchange 2003.

Unfortunately, the removal of these features isn’t just the result of running beta code. Microsoft has decided to remove them from the Exchange product entirely and create an additional messaging product.

Preparing for the upgrade
The upgrade from Exchange 2000 to Exchange 2003 happens in pieces. The first step is to upgrade the forest’s Active Directory schema to support the new Exchange 2003 extensions, and the second is to prepare the local domain for the upgrade.

To prepare the forest for the upgrade, execute setup /forestprep from the \setup\i386 folder on the Exchange 2003 CD. This will execute the same installer, but will only perform the steps required to prepare the forest for the upgrade, as seen in Figure E.

Figure E
Forestprep prepares the forest for the Exchange upgrade.

Next, you have to prepare the local domain for the new Exchange. Execute setup /domainprep from the \setup\i386 folder on the Exchange 2003 CD, as seen in Figure F.

Figure F
Domainprep prepares the local domain.

Performing the upgrade
Once you have Service Pack 3 for Exchange installed and have performed both of the preparation steps, running the installer with no switches defaults to the choice of upgrading your current installation, as shown in Figure G.

Figure G
After your two preparation steps, you’re ready to upgrade Exchange 2000.

This process doesn’t take very long and no reboot is required afterward. When you’re finished, you’ll have an upgraded Exchange 2003 installation.

When you’re finished
At the end of the process, your Exchange 2003 installation includes the new version of Outlook Web Access by default. During the installation, ASP.NET support is added to IIS 5 for this feature to work.

The new Outlook Web Access is impressive. It’s fast and it very closely mimics the appearance of the Outlook 11 client, making transition between the two very easy for users.

You don’t need W2K3 to run E2K3
Installing Exchange 2003 on Windows 2000 or upgrading an existing Exchange 2000 server can move your organization ahead by providing some new features in the messaging infrastructure—most notably the new version of Outlook Web Access—without the need to roll out a Windows Server 2003 backbone. However, not all of the new features of Exchange 2003 are accessible using this method, and some reduced functionality of the new product may be too high a cost to pay.