Firewall Flowchart

I always recommend having a Software Firewall on your computer, but the one catch is that you have to know what to do when you get an alert. It's not very hard once you've seen it once or twice, but to help you walk through it, I've made this firewall flowchart:

Click on the image for a larger view

Just start at the green oval and answer the yes/no questions to trace your way through.