On Fri, 27 Jul 2007 12:28:46 -0400, Rusty Waybrant wrote
>
> You may be seeing a similar issue as a long ongoing... What do you
> see as 'freezing up'? Do you see hung dovecot-auth processes (ps)?
> Are other services, like FTP, experiencing similar issues for the
> same users during this time? Do you notice anything unusual in your
> logs during this time (lots of failed login attempts)?
>
> I think the base issue is related to pwdb, and when you reboot your
> server, it is actually running 'dbrecover' that is actually fixing
> the issue. When this issue occurs, anything relying on pwdb also has
> a similar issue. Like FTP for the same users would also be "frozen".
We do not have any FTP users. However, all of the users
have no trouble accesing their openwebmail accounts. The POP3
server will just not make the connection for POP3 clients.
> Brian (at mark) Nuonce suggested some tweaks for dovecot.conf to enable
> auth_cache.
The dovecot.conf file already has these tweaks.
>
> You should look at your logs and try to figure out what is causing
> this... I think most of this happens for two reasons, either because
> of a dictionary-attack, or because you just have a high-volume POP3 service
> (well, these two reasons are basically the same, high-volume, either
> real-users or a 'bot' with login failures). I think someone was offering
> a reasonable priced firewall add-on that would prevent
> dictionary-attacks against POP3/FTP? So, this might be another
> option to consider.
>
The server is extremely low volume, running just for email
for about twenty total users across four domains. The logs show
periodic failed logins overnight, but no heavy dictionary attacks.
Thanks.
---Hillel