How e-mail Works

Where it Started

• The first e-mail was sent in 1971, when Ray Tomlinson sent a message successfully from one computer to another. In order to differentiate messages between users on the same computer from e-mail messages to users on other computers, Ray used the @ symbol. You used the username followed by @ and the address of the recipient computer. Although we no longer strictly tie e-mail address to places in exactly the same way, this was the basis of what e-mail is.

Preparing the Message

• E-mail starts with your e-mail client, which is the software or web interface you use to compose e-mail messages. First you need to add a header, a header requires a to and from address. Like a postmark, it stores the date and time an e-mail was sent. The header also shows you if there is an attachment, and what format the message is in. How it’s encoded.

Communicating With Your E-mail Server

·        If you’re using software such as Outlook or Mac OS X Mail etc then you’ll need to set it up to communicate with your e-mail provider and then also input the recipient’s address.

You enter two different server addresses in the setup because there is often a different server for sending and one for receiving. This is because a different protocol, or system of communication between servers, is required for each operation. For sending e-mails, a protocol called SMTP (Simple Mail Transfer Protocol) is commonly used. This protocol tells your e-mail client how to communicate with the server so it can transmit the e-mail. At this point, the information in your e-mail message is sent from your computer or web client to the SMTP server.

Transmitting to the Recipient's Server

• The SMTP server looks at the header of the message, and determines the address of the server where the recipient's e-mail account is located. Using the Internet, your SMTP server connects with the recipient's server and transmits the message. The message then goes into the e-mail inbox of the recipient, where it stays until an e-mail client downloads it, or until the message is viewed using a web interface.

Receiving E-mail

• When the recipient of your e-mail wants to send a message back, the return message follows the same path, but in reverse. When you check your e-mail using your mail client, it usually uses another protocol, POP3 (Post Office Protocol 3) to communicate with your e-mail server and request the message. The reply message is downloaded and displayed on your screen.

Sources:

http://www.oasis-open.org/khelp/kmlm/user_help/html/how_email_works.html

http://openmap.bbn.com/~tomlinso/ray/firstemailframe.html

http://www.youtube.com/watch?v=YBzLPmx3xTU