Install it as described under installing software. Start the imap daemon like this:
Verify that it is running like this:
Configure the daemon via /etc/courier-imap/imapd. The only change I did was
This line has the effect that /etc/passwd is used to authenticate the imap users.
login to server failed
If you get the error message "login to server failed", it is probably because your authentication daemon is not running. So, start it and restart courier
/etc/init.d/saslauthd restart /etc/init.d/courier-imap restart