I found Debugging authentication problems…

I edited /etc/courier/authdaemonrc and added:

DEBUG_LOGIN=1

Then I created a mail.debug log file:

# touch /var/log/mail.debug
# chown syslog:adm /var/log/mail.debug

Then I created a mail.conf file for rsyslog in /etc/rsyslog.d/mail.conf:

mail.debug /var/log/mail.debug

Then I restarted the rsyslog service:

# service rsyslog restart

Now I have debug logs for mail services!

…oh, no, wait… I only have LOGIN debugging enabled.

Found this, edited /etc/courier/imapd-ssl and added:

IMAPDEBUGFILE=courier.log

Then restarted courier imapd-ssl:

# sudo /etc/init.d/courier-imap-ssl restart

Now there is a courier.log file in: /var/pcmail/jj5@progclub.org