[Dovecot] limiting number of incorrect logins per connection

Timo Sirainen tss at iki.fi
Fri Aug 26 19:30:01 EEST 2011

login-common/client-common.h :


So set it to (45*60*1000)

But I don't think there's much of a practical difference between these.

On 26.8.2011, at 12.07, Alex wrote:

> 3 minutes! I think that's too long, how can I drop that down to about 45 seconds?
> On Fri, 26 Aug 2011 11:44:45 +0300, Timo Sirainen wrote:
>> On 26.8.2011, at 10.25, Alex wrote:
>>> Running Dovecot 2 on my server. It is regularly getting dictionary auth attacked. What I have noticed is that once connected to a pop3/imap login session, you can send endless incorrect usernames+passwords attempts. This is a problem for me... I use fail2ban to try and stop these script kiddies. The problem is that fail2ban detects the bad auths, firewalls the IP, however, since it's an "established" session, the attacker can keep authing away... It's only on a subsequent (new) connection that the firewalling will take effect.
>> Umm. If client hasn't managed to log in in 3 minutes, it's
>> disconnected (no matter what it does with the connection).

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