Nevis POP versus IMAP guide

This is a brief guide to the difference between using POP versus IMAP for mail. Normally, you choose which to use when you set up the program that reads your mail.

IMAP

With IMAP, only a copy of your mail headers is downloaded to your mail reader; the actual message is usually not copied until you select it (although many modern mail readers will also "buffer" copies of your messages to speed things up and to run filters). IMAP works very well with graphical mail readers, such as Thunderbird, Outlook, and Apple Mail.

The advantage of IMAP is that your mail messages are kept on the mail server. Your mail folders are also managed by the server. This means that no matter which computer you use to read your mail, you see the same set of messages and folders. You can even have nested mail folders.

The disadvantage of IMAP is that it' can be more difficult to set up than POP. Normally you set up options once and forget about them, but you should be aware they exist.

POP3

POP works by copying messages from the mail server to whatever computer you use to run your mail reader. Depending on the options you set in your reader, these messages will either:

• be removed from the mail server once you read them, or
• kept on the mail server until you deliberately delete them.

Most text-based mail clients (such as alpine or mutt) use POP by default.

The advantage of POP is that it's simpler to configure and think about.

The disadvantage of POP is that you have to keep track of where you read your mail. If you always login to the same machine to run alpine, this is not usually a problem. But if you sometimes read your mail using alpine on a Linux machine, and other times read your mail using Outlook on your laptop, you can lose track of which message has been stored on which machine.

Another issue is the use of mail folders, which is strongly encouraged (see the discussion on mail file management). If you use POP, your mail folders are always kept on the machine running the mail reader; if you later read your mail on a different computer, you will have different folders.

Which one should you choose?

Use IMAP. Only use POP3 if have a specific reason to do so.