How do I manually prepare my AD forest and domain for Exchange Serve 2007?

A. You must prepare AD, including changes to the schema, in advance. First, make sure you're logged on as an enterprise administrator. If you aren't logged on as an administrator, you can start a Cmd session as a schema admin/enterprise admin/Exchange admin by using

runas /noprofiles /user: cmd.exe

and running the commands from there to avoid having to log out. Run all commands from the root of the Exchange 2007 media. Here's the execution of the command Setup.com /PrepareLegacyExchangePermissions.

setup.com /preparelegacyexchangepermissions
Welcome to Microsoft Exchange Server 2007 Unattended Setup
Preparing Exchange Setup
No server roles will be installed
Performing Microsoft Exchange Server Prerequisite Check
Organization Checks ......................... COMPLETED
Configuring Microsoft Exchange Server
Updating legacy permissions ......................... COMPLETED
The Microsoft Exchange Server setup operation completed successfully.

The next command, which updates the schema, must be run as a schema admin and Exchange admin. This must also be run in the domain that contains the schema master Flexible Single-Master Operation (FSMO) role for the forest. Here's the execution of the command Setup.com /PrepareSchema:

setup.com /prepareschema
Welcome to Microsoft Exchange Server 2007 Unattended Setup
Preparing Exchange Setup
No server roles will be installed
Performing Microsoft Exchange Server Prerequisite Check
Organization Checks ......................... COMPLETEDThe Active Directory schema will be upgraded if you continue. Verify
that the organization is ready for Exchange 2007 by running the Exchange
2007 Readiness Check, which is part of the Exchange Best Practices Analyzer.
Configuring Microsoft Exchange Server
Extending Active Directory schema
Progress ......................... COMPLETED
The Microsoft Exchange Server setup operation completed successfully.
You must then prepare the AD domain, and this must be run on each domain in the forest. You can pass a domain's FQDN to the /PrepareDomain switch to run on a remote domain or use /PrepareAllDomains to configure all domains in the forest with one command. Here's the execution of Setup.com /PrepareAD:

setup.com /preparead
Welcome to Microsoft Exchange Server 2007 Unattended Setup
Preparing Exchange Setup
No server roles will be installed
Performing Microsoft Exchange Server Prerequisite Check
Organization Checks ......................... COMPLETED
Configuring Microsoft Exchange Server
Organization Preparation ......................... COMPLETED
The Microsoft Exchange Server setup operation completed successfully.