Millions of people worldwide use email on a daily basis. With its easy access, nearly unlimited storage capacity, and instantaneous communication, email has kept the world in touch with itself for more than a decade. Unfortunately, with the hustle and bustle of modern society, not that many people stop to wonder about how email and email servers work. This article will help to correct that problem by providing a clear, detailed analysis of an email server.
What is an Email Server
An email server is the physical device that stores, organizes, and transfers emails from one user to another. Email servers are critical to the entire email system. On its most basic level, the email server is just a large hard drive or computer that has been specifically setup to handle emails for millions of users simultaneously. Of course, email hosting companies do not use just one email server for their entire system but instead use hundreds or even thousands of email servers that all connect to each other to transfer emails from one person to another.
The Account
Email servers may seem complicated to some but they are actually rather simple. Email servers work by creating a separate text document that represents a user's account. For example, jbob@gmail.com would be represented as a text document called "jbob" on one of Google's email servers. Each text document contains all of that particular user's messages as well as who the message was from, the subject of the message, and the time that it was saved to the document.
Browser Mail
Browser mail is mail that is accessed through a user's browser. When the user logs on, he or she is able to read and edit their messages in an organized interface. The browser email client retrieves the information from the user's text document and displays it based on line breaks in the document that separate individual messages. Even though the messages are organized in the interface, the user is directly accessing that text document. When a user modifies a message or reads a new message, the text document is updated with that information and saves it for later use.
Client Mail
Client mail is similar to browser mail but works a little bit differently. An email client is a program that a user can download and install on his/her computer and access their email even when they are not connected to the Internet (except for new messages, of course). Email clients use the user's email address and password to request permission from the user's email hosting service's server to access the text document that contains the user's messages. Some email clients can automatically retrieve email from the server where as others must be properly setup first, depending on the server's forwarding settings. For email clients, the user can also choose whether to keep his/her emails online and send a copy to the email client or send a copy to the email client and then delete the original messages from the sever's text document.
SMTP
SMTP, or Simple Mail Transfer Protocol, is the protocol that email servers use to send and receive messages from one another. In browser mail, SMTP can be used to both send and retrieve emails to and from other email accounts and servers. In client mail, however, SMTP is usually only used for outgoing mail. The SMTP protocol takes the email address that the user has entered and requests permission from the recipient's email server or hosting service to send the user's message to that account.
POP3
POP, or Post Office Protocol, is the protocol that email clients uses to retrieve emails from the user's email server. POP is the most simplest form of email retrieval and works by connecting to the user's email server, retrieving new messages, downloading them to the user's computer, deleting the original messages from the server, and closing the session. As was previously mentioned, of course, the user can choose to not delete the original messages from the email server. POP3 forwarding settings are generally located in the Settings or Tools of the email hosting service's website.
IMAP
IMAP, or Internet Message Access Protocol, is another protocol used for retrieving a user's emails from the server. IMAP has some distinct advantages over POP, the most notable being that multiple users can retrieve emails from the same email account. IMAP is much more complicated, however, and many Internet service providers as well as many email hosting services still do not support IMAP.
