Comment 1 for bug 347881

I just reproduced this exact issue in Jaunty (dovecot 1:1.1.11-0ubuntu2). That is; I set my clock to run ahead, restarted my network which triggered a ntpdate. Hence my clock was set back to the correct time, leading to dovecot shutting itself down.

"dovecot: Fatal: Time just moved backwards by 420 seconds. This might cause a lot of problems, so I'll just kill myself now. http://wiki.dovecot.org/TimeMovedBackwards"

Today dovecot-common Suggest the package ntp. Perhaps it could at least be upgraded to a Recommends?