How E-mail Works

E-mail has been around since the beginning of the Internet. Originally it was created as a way for developers of the Internet to communicate with each other. Many people do not actually understand how e-mail works but feel they know enough from using it to explain it to others. One of the most common misconceptions is that e-mail is instant. E-mail is not instantaneous if the volume of mail suddenly increases, for example, more emails are sent during holidays. If there is a problem with a frequently used mail server, the e-mail can be backlogged for hours, or even days. Below is a diagram of the path an e-mail would take when sent from you@lehigh.edu to someone@isp.net.

1.You compose an email to be sent to someone@isp.net and click send.
2. E-mail message is uploaded to mail.lehigh.edu. Message says it is sent.
3. Your email is sorted on the outgoing mail server. First the mail server checks that the domain 'isp.net' is valid. If it is not it is sent back to you as a bounced email message. Then it checks a DNS server for the IP address of mail.isp.net and attempts to forward it.
4. Your e-mail is sent from mail.lehigh.edu across the Internet until it reaches its destination at mail.isp.net. During this process, the data from your e-mail is sent across many computers. Although it passes through many computers, none store copies of your email.
5. E-mail is recieved by mail.isp.net. It checks to make sure the user 'someone' is a valid username on that server. If not it rejects the message and sends it back to your e-mail address as a bounced email. If the username is valid it is placed in the users mailbox.
6. The user 'someone' signs on and requests to check for new e-mail message. The message is then downloaded onto their computer.
7. The message is displayed on the users computer; typically it also sends a request to mail.isp.net to delete the server's copy of the message.