Microsoft Exchange 2000 Server Adminstrator's Companion

This chapter covers the Simple Mail Transfer Protocol (SMTP), Post Office Protocol version 3 (POP3), Internet Message Access Protocol version 4 (IMAP4), and Outlook Web Access (OWA). At first glance, these might seem the sort of dry topics that only a true geek would appreciate. In reality, however, a good understanding of the basic Internet protocols will greatly assist your efforts in troubleshooting and understanding the Microsoft Exchange 2000 Server architecture.

SMTP is the native transport protocol for Exchange 2000 Server and is used by the Routing Group Connector, by the SMTP Connector (for Internet mail), and for general communications between Exchange 2000 servers. The other protocols—POP3, IMAP4, and OWA—are considered different ways to access the Store process. Understanding the advantages and limitations of each protocol will benefit your planning, implementation, and troubleshooting efforts.