Start 'er up!
Email. It is one of the most common forms of communication, and like many popular methods, it is actually extremely simple in its core. Perfect, I thought. What a great idea for an informative Virtual Science fair project. (It was a great idea! I learnt a lot more then I had expected.)
The origin of email is unclear, and whenever something is unclear to me, I pull out the dictionary. (What a geek!) It turns out, the definition is also unclear. Email is generally described as "A system for transferring messages from one computer to another, usually via a network." As a result, the definitions of a message and a network need to be further defined. In its simplest sense email was created even before the internet, when mainframes and computers used in WWII could communicate. Email evolved, and with the development of the internet, became a standardized system that could communicate between all computers rather than just a local network. This is the view I will focus on. Hopefully we shed some light on what happens from the point you click the "send" button to the time the recipient gets the message.
How does it work?
If you want in-depth coverage, you can browse through using the links at the top. Or, you can click on the coloufull links which link back and forth between pages. (This is what a link looks like; It changes colour just like the subheadings and logo). The table below shows the sequence involved in sending and recieving an email message.
| Mail Client | The first thing you do when preparing to send an email is to write the message. This is done either through a desktop mail client such as Outlook or Thunderbird, or through a webmail interface such as Gmail or Hotmail. |
|---|---|
| MIME | Once you tell the client to send the message (usually via the click of a button), the client packages up the message with headers and other information. Messages with attachments, non-ASCII characters, or heavy formatting will be MIME-Encoded. |
| SMTP | Now, our client begins a "conversation" with your mail server (often this is you ISP, such as Telus or Shaw, or your mail provider, such as Google's Gmail servers). The mail server checks the to line in the message. If the message is addressed to someone using a different mail server, your mail server begins another SMTP "conversation" with your recipient's server. If the message is addressed to someone using the same mail server as you, it is delivered immediately. In any case, the recipient server stores the message in a file. |
| POP / IMAP / Webmail | At this point, the email is sitting in a file on the recipient's mail server. The server may run a Junk-Mail filter and virus scanner. The recipient probably will open up their mail client, which will use POP or IMAP to talk to the mail server and get the message. In this case, the recipient mail client may also run virus and junk-mail checks. Then, it will use MIME to convert the attachments and formatting back into a readable form. If the recipient uses webmail, they would log in, where the message would be displayed in the web browser. |