Sams Teach Yourself J2EE™ in 21 Days

Understanding E-Mail

E-mail is something that most people take for granted without ever really understanding how it works. If you want to write applications that send and receive e-mail messages, it is essential to have some understanding of a typical e-mail system environment.

E-mail messages are sent on a client/server basis, but one that is different to that used for Web pages. Figure 11.1 shows a typical e-mail delivery process. As you can see, both the sender and recipient act as clients to e-mail servers. The sender creates a message and this forwards to an e-mail server. The server then uses the Simple Mail Transfer Protocol (SMTP) to send the message across the Internet to the recipient's mail box on another e-mail server. The receiver ...