Comment by DanOWar

Was fail2ban even working? After a reformat, did you install fail2ban manually, or from a repo? Are you using syslog or rsyslog? Each's log format is slightly different, meaning you have to edit the filter to accomodate. The base install filter didn't even work correctly for me on a fresh CentOS re-image. Also, the latest version on the website is v0.8.7.1, but on CentOS epel it's v0.8.4.