Our Active Directory environment consists of numerous domain controllers running either Windows Server 2008 Standard SP2 x86 or Windows Server 2008 Standard SP2 x64. The domain and forest are both at a 2008 functional level. We also have Exchange 2007 SP1 UR4 in the environment. We are adding another site and I need to set up a DC. I would like to set up the DC on Windows Server 2008 R2 Standard SP1. I have *no* plans in the near future to upgrade the rest of our DCs to 2008 R2 or to bring up the domain to 2008 R2 functional level. I have seen all kinds of conflicting information regarding whether or not Exchange 2007 SP1 UR4 will continue to function correctly in an environment with a 2008 R2 domain controller. I've seen some people say I need to upgrade to 2007 SP1 UR9. I've seen some people say I have to upgrade to 2007 SP2. However, according to the Exchange compatibility matrix , Exchange 2007 SP1 is compatible with 2008 R2 domain controllers, but is not compatible with a 2008 R2 functional level domain unless I upgrade to at least 2007 SP1 UR9. Do I need to do anything to Exchange if I intend to install one domain controller running 2008 R2? Keep in mind that I have no immediate plans to upgrade the rest of the DCs and raise the functional level of the domain or the forest to 2008 R2. Or should I play it safe and just install another 2008 DC? Please note that we are going to a hosted Exchange model in less than two months, and Exchange downtime until then has already been pre-emptively denied. Therefore installing 2007 SP1 UR9, 2007 SP2, or 2007 SP3 are not valid options in this case nor is waiting until our internal Exchange is gone to set up the DC.

normaly this will work. Exchange needs the Active Directory for storing the Exchange relavant information. So this configuration should be fine if you don´´t swich the functional level. But if I have to build up such an environment i will ask the question where is the benefit in using Windows 2008 R2 when it is not planned to migration the complete environment? I see a problem in supporting such an addition operating system concerning the update policy (test environment) etc. so in te end your effort will be growing without the necessity in doing so. But if you want to implement a new operating system one reason could be the lifecycle of Windows 2008 because the Mainstream Suports at 09/07/2013 regards Thomas Paetzold visit my blog on: http://sus42.wordpress.com

The main reason that I would like to install 2008 R2 is licensing. We have installed a VMware vSphere 4 cluster at this site and the domain controller is going to be virtual. We have purchased 2008 R2 Datacenter licensing for use on these VMware hosts. Adding a 2008 DC would complicate our licensing situation.

it will work with current scenrio. however if you upgrade domain fucntional level then you must first upgrade to UR9. Sajjad

Ok, I am relieved to know that installing a 2008 R2 DC will not cause issues with our existing Exchange implementation. However, another bit of fear has come up. I have discovered that two of our ten DCs are 2008 SP1 and not 2008 SP2. Will this be an issue if I plan on going forward and adding a 2008 R2 SP1 DC?

No this shouldn´t be a problem. Widnows Server 2008 R2 makes some additions to the schema but it will work. I think that a good aim would be to homogenize the Windows Server infrastructure in order to minimize the administer effort. A documentation of these changes you will find on: http://technet.microsoft.com/en-us/library/dd378828(WS.10).aspx regards Thomas Paetzold visit my blog on: http://sus42.wordpress.com