On my dedicated server (the only site on it is mine), days I do not login to any email, I always see something like this in logwatch:

--------------------- Dovecot Begin ------------------------

Dovecot disconnects:
Logged out: 320 Time(s)
---------------------- Dovecot End -------------------------
I assume that's from hackers trying to get in, but I wasn't able to find anything relative in my searches to find out what causes this.

Anyone else ever encounter this before?