How Email Works
Tuesday, May 15, 2012
When you send someone an email, you don't send it directly from your computer to their computer. A series of email servers passes your message along until it finally is read by the recipient.
Email Programs vs. Webmail
Using an Email Program
When you use an program on your computer (like Outlook or Thunderbird) to send and receive your email, the program communicates directly with your email server. To receive email, the program uses POP3 (Post Office Protocol), which checks for new incoming messages, downloads them to your computer, and deletes them from the server. To send email, it uses SMTP (Simple Mail Transfer Protocol) to send the outgoing message to your server, which delivers it to the recipient's email server.
The advantage of using an email program is that your messages are stored safely on your computer. However, to get your email, you have to use your computer.
Using Web-based Email
With Webmail, instead of using a program on your computer to compose and store email, you access an email provider's Website. When you send an email, your Web browser sends the message to the email server, which delivers it to the recipient's email server. However, incoming email is stored on the email server. You can view the message in your Web browser, but the message isn't downloaded permanently to your computer. It stays on the server.
The advantage of Webmail is that you can access your email from any computer with Internet access. Also, you don't have to update your software, since the email provider updates their interface. The downside is that your email is not stored on your computer.
Forwarders are virtual email accounts that don't store incoming messages, but forward them to another email address. For example, you could set up forwarders so that email sent to email@example.com and firstname.lastname@example.org are automatically forwarded to your personal email account. When you view the forwarded message, it will show the forwarded email address in the "To:" field. You can also set multiple recipient addresses for a forward so that the message is forwarded to more than one person.
One smart way to use forwarders is to have special email addresses that you give out to the public or use when signing up for things on other Websites. The forwarders point to your personal email account. If you start getting a lot of junk mail on that address, you can just delete the forward and the junk mail will stop.
A catch-all account receives all incoming email to any address at the domain name and forwards them to another email address. This allows you to receive email to email@example.com, firstname.lastname@example.org, email@example.com, without having to set up a forwarder for each address.
The downside to catch-all accounts is that junk mail is often sent to random email addresses (e.g. firstname.lastname@example.org) and you will get every one of them in your inbox. To stop the junk mail, you will have to set up a new junk mail filter for each new random address they send it to.
When someone sends you an email, this feature saves the message, and then automatically sends the sender an email with a message that you select.
Junk Mail Filters
Email servers can scan incoming email and filter out messages that look like junk mail before they get to your inbox. They can also check with 3rd party services that flag the IP address of email servers that send junk mail.