Uhh, k first off. Firewall's have many function's but it's primary one is to moniter and control the packet's and activity between you or the router and the internet. Second, when you are being "port probed" or portscanned, it will come up what port's you have (unless you moniter your firewall and stop the scan in progress). Why so many port's are open depend's on what services/software/etc you have running on your machine. What else do you need help with?