Describe how e-mail messages travel from sender to receiver. Include the names of the types of computers that are involved in the process, as well as the communications protocols that are typically employed.

What will be an ideal response?

When you send someone an e-mail message, it travels across the Internet to the computer at your ISP that handles outgoing e-mail messages. This computer, called the outgoing e-mail server, examines the e-mail address on your message, selects the best route for sending the message across the Internet, and then sends the e-mail message. Many outgoing e-mail servers use SMTP (Simple Mail Transfer Protocol), which is a communications protocol, or set of rules for communicating with other computers. An e-mail program such as Outlook contacts the outgoing e-mail server and then transfers the e-mail message(s) in its Outbox to that server. If the e-mail program cannot contact the outgoing e-mail server, the e-mail message(s) remains in the Outbox until the program can connect to the server.

As an e-mail message travels across the Internet, routers direct the e-mail message to a computer at your recipient's ISP that handles incoming e-mail messages. (A router is a device that forwards data on a network.) The computer handling incoming e-mail messages, called the incoming e-mail server, stores the e-mail message(s) until your recipient uses an e-mail program such as Outlook to retrieve the e-mail message(s). Some e-mail servers use POP3, the latest version of Post Office Protocol (POP), a communications protocol for incoming e-mail.