2.2 Preparing the Active Directory for Exchange

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The Exchange installation procedure includes two components to prepare the AD for Exchange. The ForestPrep component prepares a forest for Exchange by extending the schema and instantiates the Exchange organization in the configuration naming context, while the DomainPrep component prepares a domain to host mail-enabled objects, such as mailboxes, contacts, groups, and public folders, and, of course, Exchange servers.

You must run ForestPrep once, ideally in the root domain and on a server that is close (in network terms) to the schema master. You must run DomainPrep in every domain that hosts an Exchange server or mail-enabled objects, such as users, contacts, groups, or public folders. DomainPrep performs a number of functions, including creating the Exchange Domain Servers Global Security Group and the Exchange Enterprise Servers Local Security Group. As you install Exchange servers into a domain, the installation procedure adds the servers to these groups. Exchange subsequently uses the permissions gained through membership of these groups to read and modify user and configuration data.

DomainPrep also creates the Public Folder Proxy Container in each domain. The Public Folder Proxy object is an AD entry that allows Exchange to generate email addresses for mail-enabled public folders.

Initially, Microsoft did not make an explicit recommendation to run DomainPrep in the root domain of a forest if you did not plan to install any Exchange servers there. As it turns out, Exchange expects to find the public folder proxy object in all domains and if you do not run DomainPrep in the root domain, the Exchange Recipient Update Service may not create public folder proxy objects correctly. Therefore, best practice is to run DomainPrep in every domain that hosts any mail-enabled object plus the root domain.

Note that some minor inconsistencies exist between the AD schema and Exchange 2000 that force you to apply a patch to any forest that contains an Exchange 2000 server before you upgrade the forest to Windows 2003. See Microsoft Knowledge Base article 314649 for details.

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