A. A connector server is an Exchange server that doesn't have a private or public (Information Store) IS—it has only one or more connectors. Don't confuse connector servers with replication or messaging bridgehead servers. A connector server can act as a bridgehead (because it has connectors), but a bridgehead server often has public, private, or both ISs.
The chief advantage to a connector-only server is that you can update, install, uninstall, reboot, and generally abuse it without affecting your users. This is especially useful for connectors that you must frequently update, patch, or reboot (such as some third-party fax products or even the Internet Mail Service—IMS). In addition, most connectors run happily on older machines, letting you recycle older computers as connector servers. Finally, having multiple connector servers gives you redundancy for critical connections.
To build a connector server, install Exchange Server on a computer. When you run the Performance Optimizer, tell it that your server has connectors but no databases, then use Microsoft Exchange Administrator to remove the public and private ISs.