HOWTO - Run Fail2Ban in Verbose Mode to Diagnose Errors
Running Fail2Ban in Full Verbose Mode to Diagnose Errors
You can run the Fail2Ban-Client in a very verbose mode using the following commands which will show you all output when Fail2Ban is loading, this is also a useful method for tracing errors in jails, filters and actions.
Stop the Failban Server by running sudo service fail2ban stop
Make sure the Fail2Ban client is also not running by running the following sudo fail2ban-client -vvv -x stop
Then start the Fail2Ban client in verbose mode as follows sudo fail2ban-client -vvv -x start
This will show you exactly in which jail, filter or action your error lies.
Once you can start the fail2ban-client successfully using sudo fail2ban-client -vvv -x start
Then stop it again using sudo fail2ban-client -vvv -x stop
and then restart the Fail2Ban Server sudo service fail2ban restart