One of the interesting debates at the Exchange Q&A session at TEC 2012 was the question whether the upcoming release of Exchange 2013 should force companies who want to deploy the new software to upgrade their Active Directory infrastructure to a level higher than Windows 2003. Specifically, the proposal was that the deployment of Exchange 2013 within an organization should first require the Active Directory forest to run at Windows 2008 functional level on Windows 2008 R2 servers.

I should be clear that Microsoft has not put this requirement on the table and that I have seen no formal press release or other communication from Microsoft that even hints that they might move along this path. However, private conversations with a number of Microsoft engineers reveal a certain frustration that so many customers operate Active Directory based on outdated software running on old hardware. After all, Windows 2003 is now pretty elderly and is rapidly approaching the point when it becomes unsupported. Lots of people run Windows 2003 domain controllers and global catalog servers on old 32-bit servers whose best days have long disappeared in the rear view mirror.

Exchange was the first major Microsoft application to take advantage of Active Directory with the release of Exchange 2000 in 1999. This wasn’t altogether surprising because the first generation of Exchange was based on an X.500-based (loosely based in the eyes of some) Directory Service that looked, felt, behaved, and generally responded very similarly to Active Directory. The advent of a fully-fledged enterprise-quality Active Directory was good for Exchange because it could drop its own Directory Service and take advantage of a directory that was much more tightly integrated into Windows. The situation has persisted to this day.

The transition from Windows NT to Windows 2000 was slowed a tad by the need to plan for Active Directory. We learned a lot in those early days and soon became accustomed to dealing with forests and domains. Best practice slowly evolved after a few hiccups (such as the assumption that the domain is a security boundary) and the fears that administrators had about operations such as schema upgrades faded with time and familiarity.

Aside from the introduction of the Read-Only Domain Controller (RODC), which isn’t supported by Exchange, not much seems to have happened to Active Directory in terms of new functionality or dramatic new capabilities since. Or so it seems on the surface. And perhaps it’s because Active Directory is so familiar (like a comfortable old shoe) that we’ve forgotten that it’s important to keep it fresh and updated to meet the needs of new applications and new operational imperatives, such as need for increased automation.

I can’t quite work out why people would want to keep on running Windows 2003 domain controllers and global catalogs. Hopefully these are 64-bit systems rather than the antiquated 32-bit servers that Windows 2003 began upon, but even so, the facts are that Windows 2003 is old and needs to be removed from corporate computing environments. Moving to a more modern platform (my recommendation is to use Windows 2008 R2) provides Active Directory with a new lease of life with an operating system that is maintained and more secure than its predecessor. It also allows Active Directory’s functional level to be upgraded to take advantage of new features such as the recycle bin (something that should probably have been part of Active Directory from day 1 anyway).

Overall, I think that it would be a good thing if Microsoft declared that the deployment of Exchange 2013 required a modern Active Directory infrastructure. Let’s face it, you can expect that Exchange 2013 will require a schema upgrade to accommodate new features. Every other version of Exchange since Exchange 2000 has extended the schema so there’s no reason to suspect that the new version will break the habit of a lifetime now, so it’s probably a good opportunity to take a hard look at Active Directory and figure out how to improve and enhance your deployment at the same time.

Putting Windows 2003 functional level into Active Directory’s wastebasket will help Exchange too because it will reduce the complexity and amount of testing scenarios that the setup and deployment team has to go through. And if they’re relieved of the need to test deployment on outdated Active Directory infrastructures, the engineers should be able to use their time more gainfully to test new Exchange 2013 features.

I accept that some companies might have a problem if Microsoft requires Windows 2008 functional level as a prerequisite for Exchange 2013. So be it. Given the track record of every other major release of Exchange, I sincerely doubt that there will be a rush to deploy Exchange 2013 soon after general availability, so there’s plenty of time for those companies who have an issue (maybe there’s an application that depends on Windows 2003 or some form of now outdated authentication scheme that’s no longer supported) to sort things out and bring their infrastructure up to scratch.

The debate at TEC on this topic was spirited. At the end of the day, a large majority of the companies who were present saw no issue with Exchange 2013 forcing those who are stuck with old Active Directories to do the right thing and upgrade. You know it makes sense.

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