Exchange 2007 Setup

setup /PrepareAD

Creates MS Exchange Security Group in the Root Domain...and the OU contains below USGs:

Exchange Organization Administrators
Exchange Recipient Administrators
Exchange View-Only Administrators
Exchange Servers
Exchange Public Folder Administrators (new in Exchange 2007 Service Pack 1)
ExchangeLegacyInterop

This command configures global Exchange objects in Active Directory, creates the Exchange Universal Security Groups (USGs) in the root domain, sets permissions on the Exchange configuration objects, and prepares the current domain. The global objects reside under the Exchange organization container. If no Exchange organization container exists, you must specify an organization name by using the /OrganizationName parameter. The organization container will be created with the name that you specify.

This command creates the Unified Messaging Voice Originator contact in the Microsoft Exchange System Objects container of the root domain.

This command prepares the local domain for Exchange 2007.
To run this command, you must be a member of the Enterprise Admins group.

If you have Exchange Server 2003 servers in your organization, you must be an Exchange Full Administrator to run this command.

To verify that this step completed successfully, make sure that there is a new organizational unit (OU) in the root domain called Microsoft Exchange Security Groups. This OU should contain the following new Exchange USGs:
Exchange Organization Administrators
Exchange Recipient Administrators
Exchange View-Only Administrators
Exchange Servers
ExchangeLegacyInterop


PREPAREDOMAIN:

Sets permissions on the Domain container for the Exchange Servers, Exchange Organization Administrators, Authenticated Users, and Exchange Mailbox Administrators.
Creates the Microsoft Exchange System Objects container if it does not exist, and sets permissions on this container for the Exchange Servers, Exchange Organization Administrators, and Authenticated Users.
Creates a new domain global group in the current domain called Exchange Install Domain Servers. It also adds the Exchange Install Domain Servers group to the Exchange Servers USG in the root domain.

To verify that this step completed successfully, confirm that You have a new global group in the Microsoft Exchange System Objects container called Exchange Install Domain Servers.

Where to run prepareLegacy Again??

You have a domain that contains Exchange Server 2003 or Exchange 2000 Server servers, and you have not run DomainPrep

You add a new domain to your forest and you want to install Exchange Server 2003 or Exchange 2000 Server in this domain

In a new or existing domain, you mailbox-enable users who will log on to mailboxes on Exchange Server 2003 or Exchange 2000 Server servers in domains in which you have not run DomainPrep.
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Provisioning a server allows Exchange to be installed later by using delegated setup. This procedure allows a delegated account to install single Exchange servers in your domain, without being a member of the Exchange Organization Administrators group.

You can use Setup.com /NewProvisionedServer