Log authentication attempts

[j.emerlik]

We alse have same problem, now we are running Dovecot 2.2.30.2 and also use
Dovecot SASL for SMTP authentication (postfix 2.11).
We need to save all failed login attempts to database as source IP address,
username and date and time but post-login script can do this but only after
successful login. Failed login attempts information may be useful in the
fight with bruteforce attacks.
It's possible to execude some script after failed login ("Password
mismatch") ?

Regards,
Jacek