Exam Essentials

Understand that coexistence is not your only solution. You do have another way to get from Exchange Server 5.5 to Exchange Server 2003; coexistence as we ‚ ve discussed here is not the only way. A more advanced solution calls for you to install a new Exchange Server 2003 organization, most likely in a new domain, and then migrate mailboxes using the Exchange Migration Wizard. What we ‚ ve examined in this chapter is the most common and easiest method for most organizations.

Know the limitations of mixed-mode operations. Mixed-mode operations are a requirement in order to perform the migration process outlined in this chapter. However, when the opportunity arises for you to make the change to native mode, you should jump at it. When operating in native mode, you will have increased administrative flexibility to use administrative and routing groups as desired. As well, you will rid yourself of the need for the Active Directory Connector and the Site Replication Service, making your Exchange organization simpler to manage and maintain. The standard recommendation is, after you ‚ ve migrated 100 percent of your mailboxes from Exchange Server 5.5 to Exchange Server 2003, to take the Exchange Server 5.5 servers offline for a week (perhaps less in smaller organizations) and observe whether messaging occurs correctly. Once you have confirmed this, you can begin the process of permanently removing these legacy Exchange servers and getting into native mode.