In the configuration of email clients (Thunderbird, Outlook...) it is possible to choose two different protocols: POP3 or IMAP.
What is the difference between POP3 and IMAP?
POP3 stands for Post Office Protocol 3 , and is the latest version of one of the Internet's longest-running protocols (POP1 was released in 1984, POP2 in 1985, and POP3 finally in 1988.
Although minor changes were made later to POP3, this essentially remains the same tool drawn up in 1988.
It is a simple, secure and reliable protocol, also thanks to its simplicity and the very limited number of functions available.
IMAP stands for Internet Message Access Protocol ; its first version (IMAP1) was written in 1986; followed by IMAP2 (1988), IMAP3 (1991), and finally IMAP4 (1994), which is the version currently in use and which is concisely and simply referred to as "IMAP".
It is a much more sophisticated protocol than POP3, it is at least as secure and reliable, and it is much richer in features.
The two protocols are based on two completely different service management philosophies:
POP3 is aimed at completely downloading incoming messages from the server, to leave them stored on the client ; you can delete them from the server immediately after downloading them, or configure the server to delete them a certain number of days after they have been downloaded, in order to keep a "safety copy" for at least a few days.
It is a protocol that is a product of its time: at the time, the size of email inbox archives was extremely limited (5 or 10 megabytes were normal sizes...), and therefore it was unthinkable to leave the message archive on the server .
For this reason, it is a protocol that is fine for use by a single client; if several different clients are used (or if several people access the same mailbox), it is easy for problems and interference to arise (a user can download messages and delete them before his colleagues can do so, there are no obvious traces as to which user has downloaded and deleted a certain message, and it may happen that, for various reasons, the messages stored on the server are downloaded several times by the client, thus creating duplicates of them.
IMAP, on the other hand, presupposes that messages are stored on the server, also available to multiple users ; the default clients download only the message headers, while the body of the messages are downloaded only when reading is requested (it is however possible to configure the clients to download a local copy of the archives, or of certain folders).
It is the ideal protocol for managing the sharing of messages between multiple users (or between multiple different devices), which allows centralized management of archives and the creation of reliable and complete backup copies.
Which protocol to use: POP3 or IMAP?
In general, POP3 can only be used if all of the following conditions are met:
- the service is used by a single user and mainly by a single device (PC, Tablet, Smartphone) on which the mail archives are to be stored
- the webmail service is not used, except rarely
- you don't want to leave a copy of incoming messages on the server
In all other cases , that is:
- service used by multiple people who consult the same mailbox
- or the need to have a single, centralized archive of incoming messages
- or need to use different devices (PC, Smartphone, Tablet)
- or finally frequent use of the webmail service
Then the preferable choice will certainly be IMAP .
