I installed a Firewall on the PB and it drove me nuts for ages. This wanted permission for whatever and something else wanted access to a certain port.
And I found that some when you deny permission they just keep on asking, then I just gave in. A little like having a toddler.
So what's the point of a Firewall when you end up giving permission to the very thing you are trying to keep out.
Somethings were obvious, but there were a few I wasn't sure about, well more than a few.