Set Up a Debian or Ubuntu Machine as a Maildrop   IMAP: A Quick
Explanation  The mail protocol most people are most familiar
with is POP, which has long been the industry standard for
serving and retrieving e-mail. A client, which is the sort of
desktop mail program with which everyone's familiar, connects to
the POP server and says, "Do you have any messages for me?" If
the answer is yes, the client gets a list of the messages,
downloads them, and optionally either deletes them from the
server or leaves them in place. That's pretty much the entire
capability of POP.