So, having said that. If you're using transparent proxy then you likely won't be able to prevent an internal system from accessing the web ( at least, from what I can determine )ĮDIT: I believe I've found a solution when using the web filter in transparent mode. If I turn off my proxy then my firewall rules seem to work as expected. With it on, I can't seem to limit connectivity. I'm still wrapping my head around this too as it appears to limit fine grained control of systems BUT, from what I can tell, if you're using transparent proxy then manual firewall rules are ignored.