I have three Exchange Server 5.5 servers at one site. I've read that the first Exchange 5.5 server at the site is special, and that to upgrade to Exchange 2000 Server, I must upgrade the first Exchange 5.5 server either first or last—but I don't remember which is correct. Can you help me?

The first Exchange 5.5 server that you install into a site has a number of special jobs, including acting as the site's routing calculation server and hosting the Schedule+ Free Busy Information public folder. (For a list of other first-server roles, see the Microsoft article "XADM: How to Remove the First Exchange Server in a Site" at http://support.microsoft.com/default.aspx?scid=kb;en-us;q152959.) The process for migrating a multiserver site to Exchange 2000 requires you to leave the first Exchange 5.5 server alone until the end.

The simplest way to upgrade is to perform a fresh installation of Exchange 2000 on a server, then move mailboxes from an Exchange 5.5 server to the Exchange 2000 server. This process is easy when you have multiple Exchange 5.5 servers: Clean off one of the servers (but not the first server) by moving its mailboxes to another server and rehoming any public folders it contains. Then, install Exchange 2000 on the former Exchange 5.5 server and move the mailboxes back to it. Repeat this process with all your Exchange 5.5 servers until only the first server is left. At that point, you're ready to follow the instructions in the Microsoft article "HOW TO: Migrate from Exchange Server 5.5 to Exchange 2000 by Using the In-Place Upgrade Method" (http://support.microsoft.com/default.aspx?scid=kb;en-us;q324318), which explains how to upgrade the remaining server to complete the migration.