I've updated my mail server last night, from Debian etch to lenny. So far I've encountered a problem with my postfix installation, mainly that I managed to broke the IMAP access somehow.

When trying to connect to the IMAP server with Thunderbird, all I get in mail.log is:

Feb 12 11:57:16 mail imapd-ssl: Connection, ip=[::ffff:10.100.200.65] 
Feb 12 11:57:16 mail imapd-ssl: LOGIN: ip=[::ffff:10.100.200.65], command=AUTHENTICATE 
Feb 12 11:57:16 mail authdaemond: received auth request, service=imap, authtype=login 
Feb 12 11:57:16 mail authdaemond: authmysql: trying this module 
Feb 12 11:57:16 mail authdaemond: SQL query: SELECT username, password, "", '105', '105', '/var/virtual', maildir, "", name, "" FROM mailbox WHERE username = '[email protected]'  AND (active=1) 
Feb 12 11:57:16 mail authdaemond: password matches successfully 
Feb 12 11:57:16 mail authdaemond: authmysql: sysusername=<null>, sysuserid=105, sysgroupid=105, homedir=/var/virtual, [email protected], fullname=<null>, maildir=xoxo.sk/[email protected]/, quota=<null>, options=<null> 
Feb 12 11:57:16 mail authdaemond: Authenticated: sysusername=<null>, sysuserid=105, sysgroupid=105, homedir=/var/virtual, [email protected], fullname=<null>, maildir=xoxo.sk/[email protected]/, quota=<null>, options=<null>

...and then Thunderbird proceeds to complain that it cant' login / lost connection. Thunderbird is definitely not configured to connect through SSL/TLS.

POP3 (also provided by Courier) is working fine.

I've been mainly looking for a way to make the courier-imap logging more verbose, like can be seen for example here.

Edit: Sorry about the mess, I've found that I've been funneling the log through grep imap, which naturally didn't display entries for authdaemond.

The verbose logging configuration entry is found in /etc/courier/imapd under DEBUG_LOGIN=1 (set to 1 to enable verbose logging, set to 2 to enable dumping plaintext passwords to logfile. Careful.)