The fact that email technology has rendered almost every conventional communication method obsolete reflects the importance of this form of advanced communication. The surge in use of tablets, smartphones and other hand-held browsing devices has made it easy for everyone to have easy access to their email accounts. That’s why email has emerged as one of the top ways of communicating, not only for businesses but for individuals too.

Despite emails becoming a critical part of daily communication of most people and businesses, do they really understand how email works in terms of the protocols behind it and the infrastructure involved? To help people understand how emails work, we should first understand that there are four primary email protocols, each one having its own purpose and the function of its peers.

Receiving Email:

IMAP: IMAP or Internet Message Access Protocol is the most commonly used protocol among consumer email accounts. In this system, emails are stored on an Internet server. When a user accesses their account, they get connected to the external server. Data is transferred from the server to their local machine but this machine does not receive the email. IMAP provides remote access to emails and also allows one account to be operated and managed by many users. IMAP has two ports, 143 and 993, of which one must be necessarily open for the system to function.

Port 143 is the default IMAP port. It allows the protocol to listen for incoming requests to synchronize emails. Traffic through port 143 is unencrypted.

POP3: POP3 or Post Office Protocol 3 is used for downloading messages from a mail service to the local computer o the end user. They can receive emails on their own machine and have access to all their messages. The system makes it easier for the user to back up their email messages. There are other features that makes search and organization of emails more efficient. However, there are downsides too. By default, POP3 assumes that a single user will be using a specific email account. If there are multiple users, it can lead to performance issues. Synchronization of an account can also pose problems as this system is tuned to delete downloaded emails from the server by default. For POP3 to function smoothly, Port 110 or Port 995 must remain open.

Sending Email:

SMTP: SMTP or Simple Mail Transfer Protocol is the key protocol for sending email. It is the preferred mail transfer system for passing email messages from one mail server to another. SMTP does not need any authentication to function. It requires two ports of which Port 25 is the default port and Port 465 is for using SMTP via SSL.

Simple Mail Transfer Protocol

What Is The Connection Between HTTP And Emails?

HTTP or Hyper Text Transfer Protocol is not involved in the process of email exchange. It does not even get involved in the mail protocol process. HTTP and the more secure HTTPS process is the means of accessing your mail box. This comes handy when you are using web-based email services such as Hotmail or Gmail. Though HTTP is not technically a mail protocol, it plays a key role in the emailing process.

What Is the Life-Cycle Of An Email?

Now that you are fairly clear how the protocols behind email works, here is a closer look at how they actually come into play. When you send out an email, the message is sent to a mail server that’s designed to transport these emails. This server is called the Mail Transport Agent or the MTA. The MTA of the email sender used the SMTP protocol to forward the message to the MTA of the intended recipient. Once the MDA receives the email, it waits for the recipient to accept This is done either through POP3 or IMAP.

In many ways, the Mail Transport Agent can be compared to post offices while the mail delivery agents can be equated to mail boxes. This is a simple way of understanding how the whole process works.

Additional Details That You Can Use:

There are a large number of variations of the POP3 protocol. There are also many proprietary email hosting services available for your use. All the protocols and services have not been mentioned or explained here because you don’t have to know about all of them to gain an understanding of how email protocols work or how email servers go about performing their job. You might also notice the fact that you actually use different protocols to send and receive emails.