Issue Fail2ban blocks the IP addresses of a specific ISP

[Muadib24]

Hi, I have plesk Onyx 17.5.3 and Centos 6.9.
Fail2ban add every day IP from the same ISP in blacklist: Orange, and only Orange.
This is very annoying because people (and my clients) which are behind an Orange Internet Box not be able to view the websites hosted on my server.
I can (and I did) add IP in white list but I must do it every day and it does not prevent the blocking in advance.
In addition the IP addresses of this ISP are dynamic, if I add an IP to the whitelist, few days later his the new IP is blocked again.

Thank' for your help, I don't know what to do except disable Fail2ban.

 

[UFHH01]

Hi Muadib24,

pls. inspect your "fail2ban.log" and the rotated depending logs, to investigate the root cause, why an IP is being blogged, or has being blocked.
You have as well the choice to increase the log - level of your fail2ban - logs, in order to get a more verbose output in the logs.

If you need help with the investigations, pls. post the corresponding entries with the IP from the depending log ( for example "mail.log" ?!? ) , which fail2ban monitored, in order to recognize a violation in combination with the used jail - regex. Without such depending entries, people willing to you can only guess what's happening, which is a very time - consuming procedure, which might not at all fit the root cause of the violation for that specific, banned IP.