Internet Message Access Protocol: Definition & Uses

Instructor: Lyna Griffin

Lyna has tutored undergraduate Information Management Systems and Database Development. She has a Bachelor's degree in Electrical Engineering and a Masters degree in Information Technology.

In this lesson, we will understand the definition of Internet Message Access Protocol (IMAP). We will examine its characteristics and understand its uses in various applications.

What is Internet Message Access Protocol (IMAP)?

Internet Message Access Protocol (IMAP) is a standard internet protocol used for the retrieval of email messages from an email server. It primarily allows a user to access and manipulate email messages stored on an email server from their local devices (such as a laptop, smartphone, or tablet). The programs or applications installed on our devices are just receptacles for the IMAP protocol actions coming from the mail server. As an email access protocol, IMAP is the vehicle by which messages are moved, organized and manipulated between the mail server and the client application. Messages are stored and organized into various folders on the mail server. This folder structure is mirrored and synchronized to the client application.

IMAP Port Access

Like any other application on a local device, the IMAP protocol needs a logical point of connection to the internet. This logical connection is known as a port. Before any application establishes connection to the internet it has to be bound to its designated port, designated by a number. IMAP typically uses ports 143 and 993. Port 143 is non-encrypted (unsecure) and is the default port, while port 993 is the encrypted port (secure). On no account should port 143 be open and accessible to the outside world. It is an unsecure port and can be a gateway to digital eavesdropping and attacks. It is always advised to use the more secure port (993).


Compatibility with Other Applications

IMAP can be used to bridge the integration gap between email clients. One typical example is with Outlook. Outlook is a proprietary Microsoft email client that allows users to pull emails from different email service providers to their devices. Many have multiple email accounts these days. For Outlook's capabilities to be fully harnessed, it must be able to pull down emails from multiple email providers. It does so by using the Exchange ActiveSync (EAS) protocol. Not all email platforms are EAS compatible, however, and in a pool of proprietary applications, compatibility can become a major issue. If not for IMAP, Outlook use would be restricted. Without EAS availability, IMAP is able to retrieve copies of all emails stored on an any email server. Outlook therefore uses IMAP to integrate with more email providers on its platform, allowing for greater email use.

Accessing Emails from Multiple Computers

IMAP brings versatility to multiple device usage. The use of multiple smart devices today is all too common. Examples are laptops and desktops in the formal working environment, tablets on the go, and mobile phones when out on the town have become a modern lifestyle protocol. IMAP allows users to access email on all of these various devices. The email clients on these devices are automatically synchronized with the email server, making access seamless. An unopened email will be seen as unopened on all devices. The moment it is read, replied to, deleted, or accessed in any way on one device, synchronization automatically occurs across all devices to reflect the change. This also allows users to access messages without the hassle of downloading them to each connected device.

Support for Offline Access

Recent versions of IMAP like IMAP4 have enabled email programs to access messages online as well as offline. This is particularly useful in environments where internet connectivity is non-existent, intermittent, or when clients are commuting.

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