IMAP Internet Message Access Protocol: What is it, what is it for and what layer does it work on?

In order to enjoy the emails on our mobile or on the computer, there are different protocols that allow the servers of these emails to work in a synchronized way. Thanks to these tools, we can have a perfect gear in sending and receiving messages.

An important issue that characterizes the protocols is the distinction they make regarding the hosting of emails on the server. According to each one of them we will be able to see the header of the mail before opening it or downloading them directly and just reading them.

We’ll show you what the IMAP, POP3 and SMTP protocols are and how they work in our emails. We will also show you how to set up your Gmail, Outlook and Yahoo! mail accounts.

What is IMAP or Internet Message Access Protocol and how does it work?

IMAP is the acronym for Internet Message Access Protocol”. It consists of a set of certain rules that apply to the storage of e-mail messages on the Internet mail server.

Thanks to this tool, you can work directly from the server side, as it allows you to remotely access and create, modify or delete folders and files.

Our devices, download only the header of the emails, while the rest of the message remains on the server. In this way, users can choose which email to view and which not, and can modify the folder of received files.

In addition, it has the advantage that all the devices with which we can access the server of our email account, are updated automatically. This is because the synchronization is permanent, according to the requirement of the mail platform.

This is not the case with POP, which is another protocol used in the reception of email, since it works directly on our devices and the synchronization of the same is done at certain intervals.

In which layer of the OSI model does IMAP act and with which protocols does it interact?

Both IMAP for email retrieval and SMTP, used in sending emails, interact in the “seventh layer” of the OSI model. Although it is true that the user does not work directly with this level, he uses different software or programs so that these interact to reduce the complexity presented in the coding.

Remember that this level of the OSI model consists of offering all the applications to access the different services of the other layers in order to exchange data. In this way, we can realize that IMAP interacts with protocols such as SMTP or POP (which we have already discussed).

But we can also name others, which are used in the transfer of files such as FTP, or DNS to translate the codes of Internet domains, or others used to access web pages, such as HTTP.

What are all the versions of the IMAP protocol that exist?

The existing versions of the IMAP protocol are:

  • IMAP2 Protocol: In the first version and was launched in 1988. Its main function was to establish different mechanisms for emails.
  • Third version or IMAP3: Entered the technology market in 1991, but did not have much acceptance as it was a counterpoint to the access protocol RFC 1176.
  • IMAP2 bis: This version had some limitations as if the user lost the data from a computer, he could not recover the emails, since it allowed to have only one PC to interact with the emails.
  • IMAP4: This is the current version used. It was designed as a contrast to the 1991 IMAP3 version. Thanks to this one, the protocol of the users changed, since the same ones now can handle the e-mails in a direct way from the server.
  • IMAP4rev1: Created in 2003. It has the advantage of being able to listen to the emails before downloading them completely.

How to configure POP3 of the main email services?

We can configure POP3 of the main email services on our mobile device on the PC. To do this, we must perform different steps according to each of these email service operators.

Take a look!

Google Gmail

To set up POP3 in your Google Account, you’ll need to sign in to Gmail and follow this guide:

  • Go to “Settings”, this option is located at the top right of the screen and is represented by a gear icon.
  • In the top menu, choose the tab “Accounts and import”.
  • Then go to “Add an email account”.
  • At this point, you’ll need to enter your email address to attach to Gmail.
  • Press “Next”.
  • Once you have entered your address, click “Import mail from me other account (POP3)” and click “Next”.
  • Go to “Data on the POP server”. You will have to write your user name and password and in POP Server, you will have to write the name of the Port. For example, if you have a free Orange account, you will have to enter “” and “110” These data can be found on your particular mail server.
  • In this step you will have to choose whether or not to keep a copy of your downloaded mail on the server. To do this you will have to check the option “Leave a copy of the message on the server”.
  • Choose “Use SSL”, where you should enable or disable this option according to your preferences.
  • It’s time to confirm that you want to send the emails from your Google account. To do so, choose “Yes, I want to be able to send mail as…” and then select “Next”.
  • Enter the sender’s name and SMTP server data. If we continue with the example of Orange, you will have to write in “Outgoing server (SMTP)” the number “25”.
  • Once you have completed all these steps you should go back to “Add account”.
  • Select ‘Gmail confirmation – Send email as…

Copy the email confirmation code, which will be sent directly to you by Google. Once you’ve entered this code, you’ll need to review your personal settings, so you can verify that your settings are correct.

Microsoft Outlook/Hotmail

Before you can begin setting up in Outlook, you’ll need to authorize your POP account in Hotmail. To do so, you’ll need to follow this short guide:

You must go to “Options”, under “Mail” choose “Accounts” and then select “POP or IMAP”. Once you’ve done these steps you’ll need to choose “Allow devices and applications to use POP” and then you’ll need to allow “Delete messages in Outlook”. Click “Save”.

Once these steps have been completed, you should just open Outlook and follow these instructions:

  • Go to Outlook and click on “File”.
  • Then select “Add Account”.
  • Select “Manual configuration or additional server types”.
  • Click “Next” and choose “POP or IMAP”.
  • Under “IMAP and POP account settings”, you’ll need to fill in your name and other information such as your password and remember it.
  • Click on “Back”.
  • Select outgoing server and choose “Use the same settings as my incoming mail server”.
  • Click on “OK” and go to the “Advanced” tab.
  • In “Incoming server (POP3)” type “995″ and in “Outgoing server (SMTP)”, you must enter “587″.
  • Choose “TSL” in “Use the following type of encrypted connection”.
  • Then select the settings you want if you want to leave a copy of the messages on the server or not.
  • To finish, click “OK”.


In the case of Yahoo! mail the configuration is the same as Gmail, you only have to change the “Incoming mail server (POP3)”, where you will have to write “”, in the Port “993”.

In “Outgoing mail server (SMTP)” you will enter “” and in the Port “587”.

On both mail servers you should write “Yes” in “SSL required”. This way, you will have configured your Yahoo! mail in a very simple way. Remember that, if you have problems in the synchronization, we recommend you to start all the steps again. This will make the configuration a success.

IMAP vs POP3 How are they different and which is better for accessing online messages?

The differences between IMAP and the third version of POP are very clear, according to the way its parameters operate.

We show you below the most outstanding ones:

IMAP works constantly with a connection to the mail server. This allows us to have an immediate warning on our devices that an email has arrived. The same does not happen with POP3, since its way of working has a predetermined connection to the server through a time, which we can configure in intervals of 5 minutes when we enter the account to our devices.

Another important difference is that with IMAP we can see between two and three lines of the statement of the incoming email. And if it contains attachments, they will not be downloaded automatically, since we will be able to see the name and format of these. This is not the case with POP3, since we don’t have the possibility of seeing the statement because the body of the message and the attached files are downloaded together when we access the new incoming mail.

The storage that takes place, via IMAP, is done on the server. This way we can modify different folders, such as sent or drafts remotely. When working with a POP3 protocol, the storage is produced in our devices and we don’t have the option to modify anything in the server.

If we need to have more than one device accessing the server, we can do it without any problem with IMAP, since the information in each of them will be updated. This is not the case with POP3.

All folders and drafts can be read directly with IMAP, not when using POP3. Unless it is already located in our email inbox.

One of the most outstanding advantages of IMAP is that it allows you to label emails according to different categories, either by the sender’s criteria or by giving them a different importance. All these labels are hosted in the email server, so it is not necessary to modify it again when we have to enter with another device other than the main one.

POP3 allows uimaps to always have space on the server, so we don’t have to worry about deleting all the emails that are hosted on it, this way we have the advantage of always receiving the emails. This is not the case with IMAP since, if we forget to delete the emails from the server’s storage, we will not be able to admit messages over the Internet when the maximum limit is reached.

The connection time used in POP3 is short, as you only need to connect to download the email. So, if we are to use our mobile data on Smartphones, this may consume fewer megabytes contracted with any phone operator.

When we need to perform a specific search of the emails, with IMAP we will do it in an easy way. This is because the server allows us to have this certain variety of criteria.

IMAP vs SMTP Which is better and how is each different?

As we have seen so far, POP3 and IMAP are two email mechanisms or protocols used to store all the emails we have received until they are read. Afterwards, they will be stored in the server or directly in our computer.

For this to work properly, there must be other protocols that allow the transfer of electronic messages to the server or to our devices. For this there is the SMTP protocol (Simple Mail Transfer Protocol). This is a mechanism that consists of transferring the messages to the different mailboxes.

In this way, we can say that they are two technologies with different functions, but essential for the good performance of an email.

This post is also available in: Português (Portuguese (Brazil))

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