Sorry for late answer.
fail2ban settings are default (via miab-setup), firewall ufw is working.
root@box:~# fail2ban-client status
Status
|- Number of jail: 10
`- Jail list: miab-munin, recidive, miab-owncloud, miab-postfix587, ssh-ddos, miab-management, ssh, sasl, dovecot, miab-roundcube