I had another question today on AD requirements with Windows 2008. The customer has some AD servers that are Windows 2003 and will be introducing new ones that are Windows 2008. Here are some pre-req's:
Each AD site where Exchange 2007 exist needs a GC that is at least Windows 2003 Sp1 or later.
The following applies to domain controllers:
- For the release to manufacturing (RTM) version of Exchange 2007, in each domain (including child domains) where you have the Exchange Enterprise Servers and Exchange Domain Servers groups and therefore must run Setup /PrepareLegacyExchangePermissions, you must have at least one domain controller that is running Windows Server 2003 SP1 or a later version.
- For Exchange 2007 RTM and Exchange 2007 SP1, in each domain (including child domains) where you plan to install Exchange 2007, you must have at least one domain controller that is running at least Windows Server 2003 SP1.
- In each Active Directory site where you plan to install Exchange 2007, you must have at least one domain controller that is also a global catalog server and is running Windows Server 2003 SP1 or a later version.
- If you have any domain controllers that are running Windows 2000 Server, when you prepare Active Directory and domains for Exchange 2007 RTM and when you install Exchange 2007 RTM, you must run Setup.com from a Command Prompt window, and you must use the /DomainController parameter to specify a domain controller that is running Windows Server 2003 SP1or a later version. When you prepare Active Directory and domains for Exchange 2007 SP1 and when you install Exchange 2007 SP1, you do not have to specify a domain controller that is running Windows Server 2003 SP1 or a later version.
- Although you cannot install Exchange 2007 RTM on a server running Windows Server 2008, Exchange 2007 RTM is supported for use with Windows Server 2008 directory servers. Similarly, Exchange Server 2003 Service Pack 2 (SP2) cannot be installed on computers running Windows Server 2008, but it is supported for use with Windows Server 2008 directory servers.
- Exchange 2000 Server Service Pack 3 (SP3) cannot be installed on computers running Windows Server 2008, nor is it supported for use with Windows Server 2008 directory servers. An Exchange 2000 SP3 server 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 servers.
RODC (Read-only domain controllers)
No version of Microsoft Exchange uses read-only domain controllers or read-only global catalog servers. However, Microsoft Exchange works in environments that include read-only domain controllers or read-only global catalog servers, as long as writeable domain controllers are available. In these environments, Exchange 2007 effectively ignores read-only domain controllers and read-only global catalog servers.
Domain functional level
You should use at least Windows 2000 Server native for all domains in the Active Directory forest where you will install Exchange 2007 or that will host Exchange 2007 recipients.
Forest functional level
If you plan to use any of the following advanced features, the forest functional level must be Windows Server 2003 in each forest that contains Exchange servers:
- Forest-to-forest delegation. For more information, see How to Configure Cross-Forest Administration.
- Ability for a user to select the type of free/busy information that will be available to users in another forest.Disjoint namespace
A disjoint namespace is the scenario in which the primary Domain Name System (DNS) suffix of a computer does not match the suffix of the domain name where that computer resides. Limited tests were performed to validate Exchange 2007 on a computer that has a disjoint DNS namespace. These tests showed that any issues resulting from this configuration may be resolved by ensuring that the DNS suffix search list on an Exchange server references all DNS namespaces that are deployed within the organization. The list of namespaces should include not only Active Directory and Exchange servers, but also the namespaces for other servers with which Exchange may interoperate, such as monitoring servers or servers for third-party applications. For detailed information about supported scenarios with disjoint namespaces, see Understanding Disjoint Namespace Scenarios with Exchange 2007.
Single-label DNS names
Single-label DNS names are not recommended for use with Exchange 2007 or Exchange 2007 SP1. For additional information about single-label DNS names, see Knowledge Base article 300684, Information about configuring Windows for domains with single-label DNS names.
AD Ratios to Mailbox Servers
- If Active Directory is running on the x86 platform (32-bit), the recommended ratio of Active Directory directory server processor cores to Exchange 2007 Mailbox server processor cores is 1:4.
- If Active Directory is running on the x64 platform (64-bit), the recommended ratio of Active Directory directory server processor cores to Exchange 2007 Mailbox server processor cores is 1:8. To achieve the 1:8 ratio, you must have enough memory installed on the directory server to cache the entire Active Directory database in memory. To check the size of your Active Directory database, examine the NTDS.DIT file on a global catalog server. By default, this file is located in %WINDIR%\NTDS.