Hi, We've observed frequent auth failure recently from the SquirrelMail frontend. The imap server is the dovecot-1.0.7-2 from Centos 5.2. The auth backend is a pgsql database on another server. The only way to make it work is to restart the dovecot, though sometimes it'll recover automatically, but you don't know when. At first we thought there might be a network problem, but we can always run pgsql client from the dovecot server to connect and query the backend database during the auth failure. We then upgraded to dovecot-1.1.3 from atrpms.net yesterday, and still the same. It looks like the dovecot fails to reconnect/retry pgsql backend. It's the router, a H3C Quidway AR28-31 with the latest firmware VRP3.4 F0306p06, caused the problem. We upgraded it last week and found part of the database connection from the mail server were blocked by the firewall in the DB server syslog because of the bad tcp state. After revert the firmware, mail server auth act normal again.
Regards, Frank Wang