The Exchange Server 2007 Setup wizard includes prerequisite checks, Active Directory directory service preparation, and a user interface that is easy to use. For detailed instructions about how to use the Exchange Server 2007 Setup wizard, see one of the following topics:

• How to Perform a Typical Installation Using Exchange Server 2007 Setup
  
  
• How to Perform a Custom Installation Using Exchange Server 2007 Setup
  
  

To perform an unattended setup of Exchange 2007, you must run Setup from a command prompt. For detailed instructions about how to run setup to perform an unattended setup, see How to Install Exchange 2007 in Unattended Mode.

In Exchange 2007, setup includes the Active Directory preparation steps. You can prepare the Active Directory directory service and domain as part of the Exchange 2007 installation, or you can perform the Active Directory preparation steps separately before you install Exchange 2007. Preparing Active Directory includes the following:

• Preparing permissions for any computers in your organization that are running Exchange 2000 Server or Exchange Server 2003
  
  
• Extending the Active Directory schema
  
  
• Creating the Exchange organization in the Active Directory 
  
  
• Creating the Microsoft Exchange System Objects container for the domain
  
  
• Creating the following Universal Security Groups (USGs) for Exchange:
  
  
  • Exchange Organization Administrators
    
    
  • Exchange Recipient Administrators
    
    
  • Exchange View-Only Administrators
    
    
  • Exchange Servers
    
    
  • ExchangeLegacyInterop
    
    
• Setting permissions on the global Exchange configuration container, the Microsoft Exchange System Objects container, and the USGs
  
  
• Initializing domain permissions by setting permissions for users, contacts, and groups to enable Exchange servers and Exchange administrators to access and manage needed attributes
  
  

To perform the Active Directory preparation, you must be a member of the Enterprise Admins and Schema Admins groups, and you must be a local administrator on the computer. To install Exchange you do not need to be a member of the Schema Admins group, but you must be a member of the Enterprise Admins group, and you must be a local administrator on the server on which you will install Exchange.

Because the Active Directory preparation steps require a high level of permissions, you may want the administrator who performs these steps to be different from the administrator who installs Exchange. You also may want different administrators to run different steps of the Active Directory preparation. In this case, you can run Setup from a command prompt with one of the following parameters:

• /PrepareLegacyExchangePermissions
  
  
• /PrepareSchema
  
  
• /PrepareAD
  
  
• /PrepareDomain
  
  
• /PrepareAllDomains
  
  

Running Setup with any of the above parameters performs some of the Active Directory preparation steps, but it does not install Exchange. For more information about how to run Setup with the parameters to prepare Active Directory and domains, see How to Prepare Active Directory and Domains.

Note:
In Microsoft Exchange 2000 Server and Exchange Server 2003, you performed the Active Directory preparation steps by running setup /forestprep and setup /domainprep. Exchange 2007 does not have the /forestprep and /domainprep options.

You cannot perform an in-place server upgrade to Exchange 2007 on a server that has a previous version of Exchange installed. To upgrade an existing Exchange 2000 Server or Exchange Server 2003 organization, you must install a new Exchange 2007 server in the existing organization, and then move mailboxes from the previous version of Exchange to the new Exchange 2007 server.

For more information about upgrading to Exchange 2007, see Upgrading to Exchange 2007.