How Does E-mail Work?

How Does E-mail Work?

According to the nerds at Google, people on Earth send 183 billion e-mail messages a day.

As far as most of us are concerned  e-mail is magic. You type into a box, click a button on a screen, and a message is immediately delivered anywhere in the world free of charge. More than a technological innovation, e-mail is a breakthrough in interpersonal communication. Imagine talking to your friends, family, and even business associates free of charge and lightning fast. Such a thing would have been impossible not even twenty years ago.
We know that e-mail isn’t magic but most of us have no idea how it works. Read on to find out about the alarmingly easy way that e-mail works to keep you in touch with the world.

E-mail Pioneer

The first e-mail message was sent in 1971 by an engineer named Ray Tomlinson. This guy’s literally the father of e-mail and is personally responsible for all of those Viagra ads you get in your inbox every day.

Before Tomlinson’s addition to the world of e-mail, people could only send electronic messages to other users who were setup on a single redundant network. Tomlinson’s innovative idea was to give computer users the ability to send messages to other machines outside of that network using the now familiar “@”  sign to indicate to which computer the message was to be sent.

Remember that an e-mail message is essentially a very simple thing, a piece of text with a recipient ID and a sender’s ID. E-mail messages are generally short — most of my e-mail communication is less than five sentences — and even with attachments like photos or music thrown in, the computer still thinks you’re sending a giant block of text.  More on that later.

E-mail Basics

Like most of the good stuff on the Internet, e-mail runs off a server. Servers are software applications that store and deliver  information through ports — for a good breakdown on how servers work, check out this article from E-mail servers work just like any other web server, and contain “lists” of e-mail accounts — text files indicating a person’s name and account and containing their e-mail client’s activity.

When it is time to send an e-mail, your web browser connects to a port on the e-mail server, tells the e-mail server the name of the sender and recipient and saves the contents of the message to those member’s text files. That e-mail server then completes the exchange by communicating with the receiver’s e-mail server and the whole process starts again when the e-mail reply is sent.

Sure, I’m condensing the process, but in many ways e-mail really is that simple.


Since e-mails are basically complex text messages, how do attachments like photographs work?

Remember that e-mail messages can only transmit text, and since most of your attachments aren’t made of text, there must be some way of translating your niece’s smudged crayon drawing into text so the e-mail servers can handle it.

Computers these days translate attachments like wedding photos into a specific format (called MIME) and transmit that MIME material to an e-mail server using the e-mail server’s basic SMTP connection where it is then sent to the recipient just like a regular e-mail.

E-mail has changed the way we talk to each other — it has wiped out the practice of letter-writing and is starting in on phone calls.

Even though it has altered communication completely, e-mail is one of the easiest to understand computer activities — it really is just a matter of transmitting text across phone lines.

Keep in mind that though an e-mail may look complex, the basic method of transmission is straightforward and user-friendly. The next time you send an e-mail, think about all the billions of other e-mails floating around your head.

This is part of a series of blog posts we’re publishing about How Stuff Works. The other posts in this series include: