Hi Robert,
i dont understand why you focused on that ldap strings fail2ban should trigger on some "Authentication failure" regex in the related syslog
perhaps this will help to make it more clear
http://www.stefan-seelmann.de/wiki/fail2ban#postfix-and-dovecot
Yes, but I have that as well. :-)
I wanted two kinds of blockings:
#1: Everybody trying the well-known passwords (password, 123321, 1q2w3e, etc, etc) to become blocked *immediately* and for *always*.
#2: I wanted all others have to have the 'regular' settings, with three shots at typing a password, etc.
#2 being the 'regular fail2ban' settings, but during this attack, I wanted special settings, #1, for anyone trying one of the malicious passwords.
I did NOT want to have them the usual three opportunities to try.
In fact: this is a bit similar to your iptables solution, but that only works for non-ssl/non-tls connections.
Your iptables solution makes sure that thy cannot authenticate *at all*, while the above solution makes sure they can only authnticate *once*.
MJ