Exchange 2007 Compatability

Exchange 2007 Compatability with Exchange 2003

The greater the number of combinations of Microsoft Exchange and Windows server, the greater the scope for incompatibilities.  Thus each succeeding release of Exchange server produces more scope for confusion.

This page seeks to clarify these two points:
1) Which Windows operating systems support Exchange 2007 server.
2) Which other versions of Exchange server can co-exist with Exchange 2007.

Topics for Exchange 2007 Server Compatability

• Compatability between Exchange and Windows
• Planning your Exchange 2007 Server Compatability
• Exchange 2007 Server Coexisting with Older Versions of Exchange
• Backwards Compatability
• Recommendations for Exchange 2007 Server and Clients
• Summary

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Compatability Between Exchange and Windows

In a Nutshell
To make your Exchange 2007 server compatible with your existing Exchange Organization, avoid anything with '2000' in its name.  For instance, raise an Exchange 2000 organization to Exchange 2003 native.  The nearer to the ideal of Exchange 2007 server on Windows Server 2008 in an Exchange 2007 Organization, the fewer compatability problems you will encounter. 

A Practical Tip
Get the EXBPA (Exchange Best Practice Analyser) and seek out the 'Exchange 2007 Readiness Check'.  Don't wait until you have installed Exchange 2007, run the Readiness check from XP, or Vista and point the wizard to the server where you are thinking of installing Exchange 2007.  EXBPA will help you identify and correct any Exchange compatability problems.

Planning your Exchange 2007 Server Compatability

Think Like a Military General
On this current page I want to draw your attention to the top level bullet points.  Here you are planning like an army general.  On other pages I cover putting your Exchange Organization plan into action by advising on Exchange 2007 server installation and configuration.

64-bit Hardware
The first practical point is that Exchange 2007 server must be installed on a 64-bit operating system.  Talking of hardware, make sure that your proposed server features in the Windows Server Catalog (Hardware Compatability List).

Windows Server 2003 SP2 (or later)
The second point is that Exchange 2007 server can run on two types of operating system, Windows Server 2003 with SP2, or Windows Server 2008 if you have Exchange 2007 SP1 (or later).

Exchange 2007 server cannot be installed on Windows Server 2000 even if it has SP3.

Member Server
Install Exchange 2007 on a Windows server that is a member of the domain.  Bad things happen if you install Exchange 2007 on a domain controller.  One exception is the Edge Transport Role, install the Edge on stand-alone server outside of your Active Directory domain.

It is possible to install the Exchange Management tools on XP or Vista.

Clean Install of Exchange 2007 Server
You will need a fresh, clean install of Exchange 2007 server.  Attempts to upgrade from Exchange 2003 are doomed to failure.  The 'swing' technique works well to move mailboxes from an Exchange 2003 server to the newly installed Exchange 2007 server.  You can then re-build the original Exchange 2003 as Exchange 2007.

Any Edition
There is good news with 'Editions', there are no compatability problems between Exchange and Windows Server.  As far as I can see, when it comes to Windows Server operating system and Exchange editions, any combination of Enterprise or Standard editions works.  For example, Windows Server 2008 enterprise with Exchange 2007 server standard edition.  When it comes to deciding editions, don't just think short-term, 'The standard edition will save us money', but also take the long view, 'Do we need clustering?'  If so we are going to need the enterprise edition.

No virtualization
As of June 2008, there is still no option to install Exchange 2007 on a virtual server.  I repeat myself, because every time I read, 'No virtualization for Exchange 2007', I have to rub my eyes and wonder if I have made a mistake.  But, no, Microsoft do not yet support virtualization for Exchange 2007, so don't even think about trying a work-around for a production server.  Then I remember, the underlying reason is that Microsoft don't yet support any 64-bit guest operating systems for their Virtual PCs.

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Exchange 2007 Server Coexisting with Older Versions of Exchange

Native Mode
The key to installing an Exchange 2007 server amongst older Exchange versions is to raise the Exchange Organization level.  You must raise the Exchange 2003 Organization to native mode.  Now you can achieve coexistence of these three server versions: Exchange 2007, 2003 and 2000.  Note Exchange 5.5 servers are not allowed in an Exchange 2003 native organization, this is when Exchange 2007 and Exchange 5.5. cannot coexist.

Decommission Legacy Features
As ever, coexistence is never easy.  You cannot take advantage of all the new features of Exchange 2007 without sacrificing some of the legacy features on the Exchange 2003 servers.  For example: you must decommission the old Site Replication Service and the Exchange Active Directory connectors.

Exchange 2000 Lurking
If you must deploy Windows Server 2008 directory servers in a site that contain Exchange 2000, you must first hard code Directory Service Access (DSAccess).  To achieve Exchange compatability you must configure each Exchange 2000 server in the site to point to directory servers running Windows Server 2003 or Windows 2000 Server.

Backwards Compatability

At one time Microsoft were obsessed with backwards compatability, for instance, Windows Server 2003, Windows 2000 and NT 4.0 could all operate in the same domain.  So what's the problem with Exchange compatability?  The answer lies in the schema, and the heart of the problem is that Exchange 2000 is incompatible with the Active Directory schema of Windows Server 2003 and later.

The problem first surfaced with Exchange 2000 mixing with Exchange 2003 and the 'work around' was to install Exchange 2000 on a Windows 2000 member server, in a Windows Server 2003 domain.

The second problem is that while Exchange 5.5 servers can operate in Windows 2000 domains, Windows Server 2003 domains are not compatible with Exchange 5.5..  Some Microsoft bashers say that this lack of backwards compatability is laziness, others say that ditching backwards compatability allows progress.  What ever the reasons and the history, Exchange Server 2007 cannot co-exist with Exchange 5.5, and there are severe limitations if you must persevere with that 8 year old technology that is Exchange 2000.

Exchange Server 2007 is a complex topic, do you need practical hands on training?  As an MCT trainer, I can thoroughly recommend TrainSignal.  In particular, I like the way that TrainSignal cover all learning methods, instructor lead, video and of course text material.  You can either take one module, for example Exchange 2007 or go for a combination of modules.  Learn more about Microsoft Exchange Server 2007 here

Recommendations For Exchange 2007 Server and Clients

Where possible I like to keep everything in sync, thus gain maximum Exchange 2007 compatability.  Here are my recommendations.

1st Choice
Exchange Organization = Exchange 2007:  Operating system = Windows Server 2008 with Exchange 2007 Server.  On the client side, Outlook 2007.

2nd Choice
Exchange Organization = Exchange 2003 native:  Operating system(s) = Windows Server 2008 or 2003 with a mixture of Exchange 2007 and 2003 Servers.  On the client side, Outlook 2007 or 2003.

You probably can get many other combinations to work.  But the further you get from the ideal, the more new features you have to sacrifice.  In the end someone should ask the question, 'Is it worth bodging this transition?'  And: 'Would we be better to wait until we have the resources to do the job properly?'

See more Microsoft Exchange Server 2007 topics:

• Exchange 2007 Home   • SP1   • Migration   • Compatibility   • ExBPA   • Free Syslog Analyser

• Install   • Server Roles   • CAS Role   • Hub Transport  • SMTP Connector   • NDRs  • Exchange CCR

• Mailbox Role   • Create Mailbox   • Mailbox Stores   • Recipients   • OWA   • GAL   • Eseutil   • Edge

Please write in if you see errors of any kind.  Please report any factual mistakes, grammatical errors or broken links, I will be happy to not only to correct the fault, but also to give you credit.

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