I was asked to add a new email domain onto an existing Microsoft Exchange 2007 installation. The company was launching a new venture and only wanted a few people in the business to have an email address on the new domain, easy enough to do. We’ll call the new domain new-domain.com and the original working domain original-domain.com.
Started off in Active Directory by adding additional meta data to the people who were going to be concerned with the new venture into a new department, so I could use this later for the email policy. I added new-domain.com onto the department attribute in Active Directory.