How E-mail Servers Work
The process of sending/receiving an e-mail message starts with the sender who composes the message using an e-mail client. The most popular e-mail clients are Outlook, Outlook Express, and Windows Mail for the various Windows operating systems.
Each e-mail recipient has an email address that is unique and in the form:
“Somename" is the name specific to the recipient. “Domain" is the domain where the e-mail server resides. The “.com" portion of the address indicates that the domain is a commercial Top Level Domain. Other Top Level Domains include .org, .net, .co.uk, and others.
When you send an e-mail, your ISP’s e-mail server receives the mail from you and uses the domain to send the e-mail to the appropriate location. The domain is kind of like the city if you were to send a letter to someone using the postal service.
From there, the e-mail is passed on through several e-mail servers until it arrives at the intended destination. This is where the “someone" part of the e-mail address comes into play.
The “someone" part of the address tells the receiving e-mail server into which mailbox to put the message. This part of the address is like the number and street address if you were to send a letter through the postal service. Once the sending e-mail server knows to which domain to send the message, the receiving e-mail server takes over and routes the e-mail to the appropriate inbox.
E-mail servers use a variety of protocols to accomplish the sending and receiving of e-mail. For example, Simple Mail Transfer Protocol (SMTP) is used to transport e-mail from sender to recipient. Post Office Protocol (POP) is an e-mail protocol that governs how and where e-mail is stored.
To use another analogy, SMTP is like the letter carrier who receives and delivers mail for you. POP is like your mailbox where your e-mail is stored and made ready for download to your computer when your e-mail client such as Windows Mail makes the request for you.