The IMAP protocol is similar to the POP protocol because it is used to download mail. However unlike POP, IMAP just downloads the headers (not the full messages), then keeps an active connection to the mail server. While it is not as stable as POP, it has two advantages:

  • Because it does not download every message, it can handle more messages.
  • You can use IMAP to delete specific messages directly from the server.

Most mail clients support IMAP. For example, you can use Mozilla Thunderbird or many other free email programs to connect to your mail server with IMAP.