Microsoft Exchange Server 2007 and Windows Server 2008
The release to manufacturing (RTM) version of Exchange 2007 cannot be installed on Windows Server 2008. However, Exchange 2007 Service Pack 1 will be supported for installation on Windows Server 2008.
While you cannot install Exchange 2007 RTM on Windows Server 2008, Exchange 2007 RTM will be supported with Windows Server 2008 RTM domain controllers. Exchange 2003 Service Pack 2 will be similarly supported: Exchange 2003 cannot be installed on Windows Server 2008, but will be supported with Windows Server 2008 domain controllers.
Please see below for more details and for information about support for pre-release versions of Windows Server 2008 with Exchange.
The RTM version of Exchange 2007 and all previous versions of Microsoft Exchange are not supported for installation on a computer running Windows Server 2008.
Exchange 2007 SP1 (when released) can be installed on a computer running Windows Server 2008.
Management tools for the RTM version of Exchange 2007 and all previous versions of Microsoft Exchange are not supported for installation on a computer running Windows Server 2008 or Windows Vista.
Management tools for Exchange 2007 SP1 (when released) can be installed on a computer running Windows Server 2008 or Windows Vista.
Exchange Server and Windows Server 2008 Directory Servers
The following outlines the supported configurations for Exchange 2007 and earlier versions with the RTM version of Windows Server 2008. For customers running pre-release versions of Microsoft Exchange or Windows Server as authorized participants in the a Technology Adoption Program for Microsoft Exchange or Windows Server, current builds of Windows Server 2008 and Service Pack 1 (SP1) for Exchange 2007 are also supported as described below.
Exchange Server 2003 Service Pack 2, Exchange 2007, and Exchange 2007 SP1 (when released) are supported in environments that either partly or entirely use writeable Windows Server 2008 directory servers.
Exchange 2000 Server Service Pack 3 and all previous versions of Microsoft Exchange are not for use with Windows Server 2008 directory servers. The following restrictions apply with respect to Exchange 2000 Server Service Pack 3:
Exchange 2000 Server Service Pack 3 can exist in an Active Directory forest that contains Windows Server 2008 directory servers, but Windows Server 2008 directory servers should not be installed in Active Directory Sites that contain Exchange 2000 Server.
If Windows Server 2008 directory servers must be deployed Active Directory Sites that contain Exchange 2000 Server you must first hard-code directory service access (DSAccess) on the Exchange 2000 Server servers in the site to point to directory servers running Windows Server 2003 or Windows 2000 Server.
No version of Microsoft Exchange uses read-only domain controllers (RODCs) or read-only global catalog servers (ROGCs). However, Microsoft Exchange works in environments that include RODCs or ROGCs, as long as there are writeable domain controllers available. Exchange 2007 effectively ignores RODCs and ROGCs. Exchange 2003 also ignores RODCs and ROGCs in default conditions where Exchange components automatically detect available domain controllers. No changes were made to Exchange 2003 to make it read-only directory server-aware. Therefore, trying to force Exchange 2003 services and management tools to use RODCs may result in unpredictable behavior.
Upgrading Exchange 2007 from Windows Server 2003 to Windows Server 2008
When upgrading standalone servers, it is not supported to upgrade your operating system to Windows Server 2008 and then upgrade Exchange 2007 to SP1. It is also not supported to upgrade Exchange 2007 to SP1 and then upgrade your operating system to Windows Server 2008. To deploy Exchange 2007 SP1 on Windows Server 2008, you must install Windows Server 2008 on a computer that does not have Exchange installed, and then install Exchange 2007 SP1.
For clustered mailbox servers, Exchange SP1 introduces support for clustered mailbox servers running on Windows Server 2008. However, as a result of the significant changes introduced in Windows Server 2008 failover clusters (called server clusters in previous versions of Microsoft Windows), rolling upgrades of a failover cluster from Windows Server 2003 to Windows Server 2008 are not possible. Therefore, to upgrade a clustered mailbox server from Windows Server 2003 to Windows Server 2008, you must build a new failover cluster using Windows Server 2008 as the operating system for all nodes, and then migrate the data from the old cluster to the new cluster. You can use the Move Mailbox operation to move mailboxes from the old cluster to the new cluster, and you can use public folder replication to move any public folder data from the old cluster to the new cluster.
Known Issues with Exchange Server and Windows Server 2008
The following are known issues when combining legacy versions of Microsoft Exchange with Windows Server 2008:
Setting an Exchange 2003 domain Recipient Update Service to use a RODC will succeed, but user accounts will not be updated by the service. It is also possible to force the Active Directory Connector (ADC) service to use an RODC, but this will cause the ADC to function incorrectly.
Exchange 2003 may not install correctly in a pure Windows Server 2008 forest if you try to install Exchange in a child domain without installing Exchange in the parent domain.