A Guide to How E-mail Servers Work

A Guide to How E-mail Servers Work
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E-mail is such a part of our lives that we rarely stop to think about how e-mail servers are able to deliver e-mail all around the world at lightning speed. This article provides a definition of an e-mail server and explains how an e-mail server works.

E-mail Server Definition

An e-mail server is nothing more than a computer that server as an electronic post office for e-mail messages. The typical e-mail server consists of both hardware and software that is capable of receiving and sending e-mail messages to and from other servers that take part in the e-mail exchange process.

The software used by e-mail servers run standardized protocols such as SMTP and POP3 so that they can communicate with one another. Both private Internet Service Providers (ISPs) such as RoadRunner and Comcast as well as public e-mail providers such as HotMail (Microsoft) and Gmail (Google) use e-mail servers to provide their services to customers.

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:

[email protected]

“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.


Among other networking protocols, the protocols that are used to deliver and store e-mail messages are quite simple. This is one of the reasons why e-mail is so fast. There isn’t much hardware and software between you and the recipients of your e-mail messages to slow things down.

The most common protocols are SMTP and POP and have been around since e-mail first became popular with the public in the late 1980s. Until there is need for most sophisticated e-mail delivery and storage, these protocols are likely to stay with us for many years to come.