Changes

# At this point you should be able to understand any iptables rules you'll see in this course, including the default ones in CentOS. If you see a rule you don't understand - you can delete it and see what happens. But if you do that - spend some time figuring out what that rule did and why you needed to delete it. It was likely there for a good reason.

It will print out a menu of exercises. You can pick any of them in any order. The script will first reset the firewall settings to CentOS defaults and then make some modifications from those defaults.