POP vs. IMAP email Protocols

Difference between POP and IMAP email protocols

Emails have become an important part of our life and business and today we do not use only computers for sending emails. This is why the need for POP and IMAP has arisen. POP or Post office protocol and IMAP or internet message access protocol are used when you receive emails from the mail server while SMTP or simple mail transfer Protocol comes into picture when you send emails.

POP is a protocol which is used for downloading emails from the central mail server.  Like in the case of MS Outlook Express or MS Outlook this POP allows downloading of the emails from the server to the local computer and then it deletes the emails from the server. The connection established by TCP and UDP is disconnected.  There is an option and if you want to leave the emails in the mail server, you can do that but it is usually not a practice. The mail servers have use spaces which are measured in Terabytes.

Port 110 is used for listening to the POP requests in secure mail services and Transport Layer security or Sere Socket Layer is used for establishing connectivity with the mail server by using STLS command or POP3S.

IMAP server listens on port 143 for the requests to deliver emails from the server. In this protocol the emails can be accessed by clients anywhere because they are stored in a central system. It is kind of a remote desktop connection. For viewing the email client running at a remote location you simply need to use a remote desktop application. It has far more advantages when compared to POP.

The email clients can stay connected with IMAP server till the time the user interface is active. As the mails are stored at a centralized location multiple clients can access the emails simultaneously. The email clients can retrieve just a part of the message without downloading the entire message or the attachment. You can get the information about the status of a message as if it read, flagged, replied etc. The changes made to the mail boxes by the IMAP clients are saved on the server as well and the IMAP client can perform the search over the server.

Here are some differences between POP and IMAP:

1. In case of POP the mails are downloaded to the local system while in case of IMAP they are stored at a centralized location.
2. POP listens to port 110 while IMAP uses 143.
3. POP disconnects from the server after downloading the mails while IMSP remains connected.
4. In POP the mail folders are kept in the local computer while in IMAP they are kept in the server.
5. You get message stats in IMAP while in case of POP the mails are deleted once you download them to the local device.
6. You need to scan all the mails once you have downloaded them to the local device in case of POP while virus scans are easy in case of IMAP.
7. In case of POP you need to perform the search on the local system while in case of IMAP you do it on the server.
8. The chances of losing data are more in case of POP in the cases when the local device crashes while data is safe when it is saved in the server.