Block spam IP with fail2ban

==== Required information ====
- iRedMail version: I Don't know where i can see that version. I've iRedAdmin-Pro v1.8.2
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MYSQL
- Linux/BSD distribution name and version: Debian 7
====

Hi, first of all i'm sorry for my english.

My question is about how i can ban sender IP with fail2ban on error. i've seen that postfix-iredmail.conf have that rules, but no ip is banned...

Status for the jail: postfix-iredmail
|- filter
|  |- File list:    /var/log/mail.log 
|  |- Currently failed:    0
|  `- Total failed:    0
`- action
   |- Currently banned:    0
   |  `- IP list:    
   `- Total banned:    0

"fail2ban-regex /var/log/mail.log /etc/fail2ban/filter.d/postfix.iredmail.conf" shows about 7244 matches, but still no working.

What i've to do to make it work?

EDIT: After 20 minutes, the above command shows 7533 matches, but none is banned :S
Fail2Ban version is 0.8.6