How E-mail Works – Anatomy and Function

How Email Works

E-mail, short for “electronic mail” is one of most widely used forms of digital communication. It can be used from nearly any device, and unlike paper mail, it is delivered nearly instantly. E-mail is used in all strata of society, and has endless possibilities for personal and professional uses.

It can be used to send messages, links, images and files, essentially everyone on the planet who uses computers will use e-mail. It powers business and connects families together across continents, and the best part of all is that it is essentially free. People use e-mail on personal computers, mobile phones, tablets, even on ‘smart' televisions!

Basics of E-mail

Every e-mail address has an inbox. This is where new messages are deposited. An e-mail message has a status called “unread” which disappears after the e-mail has been opened. A typical e-mail inbox will also have a ‘Sent' folder for viewing messages that you have sent in the past. It also will have an ‘Outgoing' folder, where messages stay until they have been fully transmitted. It is also common to have a ‘Drafts' folder for messages that were started but never sent, and a ‘Spam' folder, where unwanted marketing messages will usually be directed. You can of course setup your own folders and sort your e-mails however you like.

An E-mail message has a Sender, and it can have multiple recipients. Using either the To line, the Carbon Copy (CC) or Blind Carbon Copy (BCC) – e-mails are delivered to the addresses listed in those fields. The e-mail has a subject line, a message body, and it can have file attachments. For more information about how messages are structured, you can read about the anatomy of an e-mail.

Origin of E-mail

The origins of e-mail date back as far as the 1960's, when the Massachussets Institute of Technology (MIT) invented something called the “MAILBOX” for sending text between computer terminals on a single mainframe. Then in the 1970's, the US Department of Defense began it's ARPANET program, which is the origin of the modern internet. The early ARPANET had a project in 1972 which was the first time that the @ symbol was used to denote the location of the message sender. By 1976, over 75% of ARPANET traffic was considered to be e-mail, saving the platform and paving the way for future of the internet.

The late 1980's saw the rise of  the personal computer (the PC), and local-area network (LAN) ‘electronic mail' became common within corporate networks. This is the period where most of the messaging encoding protocols we use today were originally conceived and became international standards. By the time that commercially available internet became available to consumers in the early 1990's, e-mail was a well established concept and came bundled in most internet service packages. So e-mail has existed for as long as the internet has, and perhaps is very reason the internet exists in the first place!

How E-mail Moves Across the Internet

E-mail works in a fashion similar to traditional paper mail. When you put a letter in your mailbox, it does not get taken directly to the recipient. First it gets brought to your local post office, where the post office employees figure out where your mail is going to be sent. They decide which destination post office has the mail route to deliver the message to the recipient. So the trail of the message goes from your mailbox to your post office, and then to another post office, and finally to the recipient. The letter might even travel across multiple post offices before being sent on the final delivery route.

This same process approximately happens in e-mail. A mail client sends the message to your mail server (which is owned by the website listed after the @ symbol) and that gets sent by a “mail transfer agent” to a mail exchanger (MX), then to a mail delivery agent (MDA), and finally to the recipient's inbox. While this sounds complicated, this all happens behind the scenes. An interesting fact is that the modern global postal system uses machine vision and coded numbers for routing mail and packages, and might be considered more complicated than e-mail.

Don't worry too much about how e-mail infrastructure works. The import concept to understand is that your e-mail inbox relies on a mail server, which is run by the website listed after the @ character. So if you have a business e-mail address, the company owns and operates a mail server to handle your messages. Or if you use the e-mail provided to you by your internet service provider, then they are the ones who own and operate your mail server. Or you could perhaps setup your own website, and pay for a web host to run a mail server for you.

Different Protocols?

If you are setting up your own e-mail, you might be asked whether you are using POP, IMAP, or Exchange. These are just different e-mail encoding methods, you will need to ask your e-mail provider which one is used, and what Simple Mail Transfer Protocol (SMTP) address to use. Every e-mail server will have an SMTP incoming address and outgoing address, as well as a “port number.” When you ask your e-mail provider for this information, it will usually come with instructions on how to set it up for popular e-mail clients like Microsoft Outlook. You probably also have a help-desk or IT support phone number you can call if you get stuck.

What is Webmail and How is it Related to E-mail?

Webmail (or web-based e-mail) is still e-mail, it's just using a website for  your e-mail client instead of a desktop application. There is no real technological difference on how the message gets sent. The only user-facing difference is that with webmail, an internet connection is required to read your messages, whereas with a desktop client the messages are downloaded to your computer and can be read without an internet connection. For more information, you can read all about webmail here.

Why Use E-mail?

Electronic mail, or e-mail, is the most frequently used service on the Internet for many reasons. Using e-mail, you can:

• Send a message anytime, anywhere and the recipient can read it at his or her convenience.
• Send the same message to multiple recipients.
• Forward information without retyping it.
• Send messages fast, usually taking no more than a few seconds to be received.
• Attach digital files to your messages, including electronic documents, video clips, music and photos.
• Send messages around the world as easily as to someone down the block.
• Communicate from any device: computer, tablet, smartphone, even some watches.

E-mail has revolutionized the way people communicate. Whereas once it took days to send a letter across the country, now you can send a note to someone across the world in a matter of seconds. That means correspondences can now happen in near-real time, businesses can collaborate from any location, and families can keep in touch from around the world.

Anatomy of an E-mail Message

The software program you use to send, receive, and manage electronic messages is called an e-mail client. Regardless of what e-mail client you use, the fields you fill out will always be the same.

Standard Fields

• To: contains the e-mail address of the recipient, and tells your mail server where to send the message. This is a required field.
• Subject: contains the main topic of the message. Keep this brief. Recipients see this in their summary of incoming messages.
• Body: contains the message itself, which can be of any length. While you can send an e-mail without anything in this section, that would be like mailing an empty envelope to someone.

Optional Fields

• CC:, short for Carbon Copy, contains the e-mail addresses of people other than the primary recipients.
• BCC:, short for Blind Carbon Copy, contains the e-mail addresses of other recipients who receive copies, but their names and addresses are hidden from all other recipients.
• Attachments contain the names of files that you may be sending, for example, a Word document or a photo. Read more about Sending Attachments here.
• From: This field will contain your own e-mail address. You should not have to touch it unless you have more than one e-mail account set up and need to switch between them.

Technically speaking, the only field you absolutely have to fill out in order to send an e-mail is the “To” field, but the subject and body of a message are what makes it worth opening, so don’t leave them out! It’s possible you will never need to use the optional fields above, and that’s okay. But if you do need them, it’s good to know they’re there.

Here is an example of a simple message with your Standard Fields and an attachment:

How do I send the perfect e-mail?

What really matters is audience and context. E-mail is a form of instant communication, and most people receive hundreds or thousands of e-mails per day. With that in mind, try to keep your messages concise and to the point. If you are sending a marketing e-mail, put your CTA somewhere easy to see. If you're sending someone an e-mail with questions, put those near the top or bottom so that it's clear what you need help with. If you want to know more, you can learn about understanding e-mail etiquette.

 

Frequently Asked Questions

Can two people sign up for the same e-mail address?

No. If you consider the domain name portion of an e-mail address to be your post office, think of the user name portion as your PO Box number. If two people were to use the same user name and domain name combination, it would be impossible for your mail server to distinguish between the two. To solve this, when you sign up for an e-mail address, you will be advised if your name has already been taken and offered several alternative addresses you can choose from.

If you want to use your own name for your e-mail address, you may need to try a different e-mail provider, or sign up for your own domain name.

Of course, this is not to say you can’t share an e-mail address. Just as you can share a PO Box with your family, you can let them use your e-mail too. But you’ll have to wade through all of their messages and vice versa.

Do I have to type the address perfectly when I send an e-mail?

Unfortunately, yes. e-mail servers have to be very specific. A slight misspelling could result in your message getting bounced back to you (because that address does not exist) or, worse, arriving in a stranger’s mail box. That’s why it’s important to double-check your spelling. Or, if you are e-mailing someone that has already sent you a message, open their old message and click reply.

What if I don’t know the exact address?

There are several ways to locate an e-mail address, which we’ll cover in more detail in Finding Addresses. If you’re e-mailing someone you know, the best thing is to give them a call. Or you could send them a letter…if you have the patience for that sort of thing.

Can I sign up for the same user name as someone else, but with a different domain?

Yes. While e-mail addresses must be unique, it is fine for the same user name to be used with different domain names. For instance, if bob.smith@coole-mail.com is already in use, you could sign up for bob.smith@evencoolere-mail.com. In fact, many people have the same user name for multiple domains, allowing them to use each address for a different purpose, such as one for personal communications and one for business.

Is there a benefit to using e-mail at work?

Absolutely! While nothing will replace a good face-to-face meeting, e-mail is a great way to get questions answered quickly. Let’s say you are working on a presentation and you have questions about several parts of your business. Rather than circling the entire office, hoping every person you need to talk to is there (if everyone is even in the same office), you can simply shoot an e-mail to all of your project stakeholders at the same time. Then they can respond to the questions that apply to them, and maybe even help out with some that don’t. If someone isn’t available right then, they can get back to you when they are free. No need to track them down.

Another benefit of e-mail at work is that you always have a record of what’s been discussed. In fact, many e-mail programs now allow you to group messages from a single conversation, so you can quickly follow any back and forth discussions.

Does it take longer to send e-mails over greater distances?

The time it takes for an e-mail to be delivered has more to do with the mail servers than the actual distance. This is because things move very quickly between two points on the Internet. While it may take slightly longer to send a signal across the world than next door, that time difference isn’t noticeable. On the other hand, if a mail server is busy or running slowly, or if it has extra security checks in place to reduce spam or scan for threats, it could take longer for your e-mail to be received. In fact, it’s entirely possible that sending an e-mail to your next door neighbor could take longer than sending an e-mail to someone on the other side of the globe.

 If e-mail is so fast, should I be concerned if I don’t receive an e-mail within a few minutes?

Probably not. Several factors can cause e-mail delays. If your mail server is experiencing heavy traffic, it may take longer for messages to reach you. If there is a technical problem, or if your mail server is undergoing system maintenance, the message could be delayed. It’s also possible that the sending server is experiencing delays. Unless it’s an urgent e-mail, give it an hour or two. If you haven’t received it by then, send a message the sender to double-check that 1) it was sent and 2) your address was typed correctly.

Can I attach anything to an e-mail?

Most mail servers place some size limits on attached files, to prevent a single e-mail from clogging their resources. These limits are usually fairly large, so unless you are sending large video files or several photos in a single message, this shouldn’t be a problem. You can learn more about attachments in our Sending Attachments article.

I don’t see a BCC field. Where do I find it?

Sometimes e-mail clients will hide the BCC field from the standard message window. This is because it is used less often than the other fields. To add a BCC field, you may need to search your e-mail client’s options menu system for a “show fields” option. If you have trouble finding it, consult your e-mail client’s help system.

Do I have to include a subject?

Not technically, but you should. Most e-mail programs will warn you if you try sending a message without a subject. This is because messages without subjects are often marked as spam, either by the recipient’s spam filter or the recipient themselves. Adding an appropriate subject is a good way to let the recipient know they can trust this message.

What type of files can I attach to an e-mail?

You can attach any type of file to an e-mail; however, most e-mail servers have size restrictions for attachments, so very large files may be refused either by your mail server or the recipient’s. If you need to send large files, or a large number of files, it is better to share them using an online storage system, such as Dropbox or Google Docs.

How do I know what to write in the subject line?

Your subject should be a brief, clear summary of the body of your e-mail. The subject is the first thing the recipient will read when they receive your e-mail, so use it to set expectations for what they will find inside. For more information, see E-mail Etiquette.