What Is Email | How Does Email Work | Email Protocols | IMAP, POP3 And SMTP Explained


Email is one to one messaging over the Internet. Email is the messages stored on the computer and can be sent to anyone. The messages are in text format and multimedia can also be included. Email is one of the first use of Internet. It was first introduced in 1960 and very soon it acquired the role of official communication. Email is quite a old technology but is as robust as nothing, no other can take place of email.

Email is part of our day to day life. Every important communication is done over email. It is very convenient and is environment friendly, as it saves paper. Emails can be accessed from anywhere like our computers or smartphones. But, what makes them so easy to be used and accessed from anywhere? Here we will try to find out how email work and what are the rules or protocols which makes them work so efficiently.

How Does Email Work

Email work on same client and server principle. User uses a email client to compose and read the message and server handles all the back-end stuff. Let’s see step by step how email work.

  • User composes the message using a email client or web mail. Email client is a software which resides on our computer and is used to send and receive emails. Microsoft Outlook or Thunderbird is a example of email client. Web mail is web application which works on Internet browser and allows user to send and receive email messages.
  • After sending the message the email is stored in the SMTP server. SMTP(Simple Mail Transfer Protocol) server is server which allows a user to send the emails to another user.
  • SMTP server looks for the recipient’s email address in the DNS server record. If the record is found the message is send to the found address else the message sending fails.
  • Same as SMTP server there is a email server which takes care of Incoming messages. User has email clients configured with these servers.
  • If a new message is available on the email server, user can access them via email client or web mail client.


Email Protocols

Protocols are set of rules which defines working of specific thing. Every technology has set of protocols on the basis of which it is easy to use the technology. Protocols make the use of a thing uniform. Email has such set of protocols which enables us to use email service in standard way.

Email has mainly three protocols. Two for accessing email messages from the server and one for sending message. IMAP (Internet Message Access Protocol) and POP3(Post Office Protocol 3) are used for accessing the emails from the servers. SMTP(Simple Mail Transfer Protocol) is used for sending the emails from one server to another. All these protocols work upon the IP (Internet Protocol).

POP3 (Post Office Protocol 3)

POP3 is very first of it’s kind. This was the first standard protocol used for accessing email and the first version was introduced in 1984. Till today POP3 is the famous protocol for accessing the emails. POP3 was meant to work on very different Internet than we have today. In earlier days computers were having very limited access to the Internet.

Like the post office, the message which is meant for you is delivered directly to you without retaining the copy of message at the central office. In simple words, in POP3 a email client is configured with the email server and the email messages are directly downloaded to the user’s computer without retaining the copy of the message on the server. But, you can choose to keep a copy on server as well.

POP3 works off-line as it downloads all the new mails on local configured machine. Here mails cannot be accessed using a web mail client. This protocol works in such way because, at the time of finding the protocol, the computers had limited access to the Internet.

IMAP (Internet Message Transfer Protocol)

IMAP was introduced in 1986. But is the most famous protocol till date as it suits all the modern needs. The concept here is to keep the emails over cloud so that the user can access the email messages from anywhere i.e. email client or web mail.

IMAP allows the user to access the email messages from multiple mediums at the same time. Unless user deletes the email from server the he/she can access it from anywhere.

IMAP does not work offline. All the messages are not downloaded by default. The header of the email is only downloaded at first. If users chooses to open the particular email then the complete message is downloaded. User can delete the email without even reading it.

IMAP has a issue of limited mailbox size as the emails are stored over remote computer. And the remote computer might have less storage capacity. But you can always archive your emails on your local computer.

SMTP (Simple Mail Transfer Protocol)

SMTP is responsible for delivering the email message to the right recipient. After user send the message it is stored over the SMTP server. Now it’s SMTP server’s duty to drop your message to intended user.

SMTP server is only used to send the emails and not to receive them. SMTP server does not require any authentication. But this is a disadvantage as any user can send the email to another user. Lack authentication in SMTP has gave birth to spam emails.

This was pretty much you should know about email and email protocols. We would love to hear from you if you something to add. If you have any questions shoot them in comment section below.

Happy Learning!

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