As well as modifying the Windows 2003 or Win2K schema, Forestprep performs another important task: It creates the Exchange container object within the AD Configuration Naming Context. The Exchange container object is the AD branch that holds information about the configuration of all Exchange servers within the organization. Exchange 2000's version of Forestprep requires you to enter the name of the Exchange organization during creation of this object, then writes that name to AD at the first level within the Exchange container object. Therefore, you must decide on your organization's name even before you install the first Exchange 2000 server. Exchange 2003 resolves this minor irritation. Instead of requesting an Exchange organization name, Forestprep writes a placeholder globally unique identifier (GUID) to the Exchange container. This GUID is consistent across all installations and has the value {335A1087-5131-4D45-BE3E-3C6C7F76F5EC}.
You don't need to execute Forestprep on the Schema Master, but you must execute Forestprep on a server in the domain that holds the Operations Master. (Typically, the Operations Master is the first DC installed in the Windows forest, but you might have moved the Operations Master role to another server.) If you attempt to run the Forestprep utility on a server in a different domain, Setup will stop and display a message specifying the correct server. The executing server uses an LDAP bind to perform the necessary LDIF operations against the Operations Master.
The account from which you run Forestprep must be a member of the Enterprise Administrators group, the Schema Administrators group, the Domain Administrators group, and the Administrator group on the local machine. Forestprep also asks you to designate an existing Windows account from which to run the Exchange Administration Delegation Wizard, which you use to assign specific Exchange administration roles to other Windows administrative accounts. You can then use these other accounts to install and manage subsequent Exchange 2003 installations.
Expect to see relatively light CPU usage on the server from which you run Forestprep, but expect to see heavy CPU usage on the Schema Master, which acts as the target for Forestprep's LDIF operations. (Most LDAP operations on a Windows server consume a lot of CPU resources.) You can expect to see 100 percent CPU usage on a one-processor Schema Master for the duration of the LDAP operations. Because the LDAP threads in lsass.exe (the AD process that consumes the CPU resources) aren't multiprocessor aware, a two-processor system will max out at 50 percent usage for the duration of the LDAP operations, a four-processor system will max out at 25 percent usage, and so forth. Performing the schema extensions on my test Schema Master, a one-processor 500MHz Pentium III system with 256MB of memory, took about 19 minutes.
Running Domainprep
Before the first Exchange 2003 installation, you must run Domainprep in each domain that will hold an Exchange 2003 or Exchange 2000 server or mail-enabled objects (i.e., Exchange mailboxes or Contacts with associated Exchange addresses), regardless of whether you've run Domainprep during an earlier Exchange 2000 installation. Domainprep creates the Exchange Domain Servers global security group and the Exchange Enterprise Servers local security group in each domain. Each subsequent Exchange 2003 server that you install joins these groups; membership lets the Exchange servers read and modify user and configuration information.
Domainprep also creates a Public Folder Proxy container in each domain in which you execute it. This object is basically an AD entry that holds email addresses associated with public folders so that users can send email to those folders. Exchange 2003 and Exchange 2000 also expect to see a Public Folder Proxy container in the forest's root domain, so you must execute Domainprep from that domain whether or not it contains any other Exchange servers or objects.
Domainprep's permission requirements aren't as severe as Forestprep's requirements. The account from which you execute Domainprep must be a member of the Domain Administrators group and the Administrator group on the local machine.
A Smooth Transition
Familiarity with Exchange 5.5 deployment concepts did little to help you understand the necessary Exchange 2000 planning activities because Exchange 2000 brought a sea of change in terms of underlying concepts and AD technologies. The transition from Exchange 2000 to Exchange 2003, however, is markedly different. Preparing for and installing Exchange 2003 involves the same concepts and—for the most part—tasks as Exchange 2000: correctly deploying Windows DCs and GC servers, verifying connectivity, running Forestprep to install schema extensions, and running Domainprep here, there, and everywhere. Exchange 2003 is designed to simplify deployment, and the changes in the installation process accomplish the job.