Why This Chapter Matters

In a clustering environment, Exchange Server 2003 runs as a virtual server because any node in a cluster can assume control of a virtual server. If the node running the Exchange virtual server experiences problems, the virtual server goes offline for a brief period until another node takes control. Exchange Server 2003 installs as a virtual server in both Microsoft Windows clusters and load balancing clusters. Load balancing and failover protection are important features of any email system.

Exchange Server 2003 Internet protocol virtual servers provide Simple Mail Transport Protocol (SMTP) resources that handle relay and e-mail delivery, Hypertext Transport Protocol (HTTP) resources that provide Web-based access to Exchange mailboxes and public folders, and Network News Transfer Protocol (NNTP) virtual servers that provide access to newsfeeds. Virtual servers can also be configured to provide access to e-mail messages for Internet Message Access Protocol version 4 (IMAP4) and Post Office Protocol version 3 (POP3) clients.

Virtual servers carry out essential functions within an Exchange organization and are likely to be tested extensively in Exam 70-284.