This is what I need to do: if mod_security rule is a match, then I want to add the ip address where the request came from to the firewall's block list
The idea is that if someone attempts to post spam to my form, a security rule will catch that using the list of pre-defined spam words and then I want
to add that IP address to firewall so that it will be clocked from accessing my server ever again.

Basically I just need to execute an external command from mod_security when the match occurs and pass IP address to it.

Does anyone know how to do that?