Just a heads up, so you guys don't overly dwell on areas that really are kinda moot these days.
most hacking is done via java or activex or windows exploits or moron-run double-click programs or installed spyware or hackware with legit programs. Port-Scanning and other shit is sooo 1994. I do'nt know any hackers that still waste their time trying to get past firewalls and shit. There's so many more EASIER avenues to exploit.
Like someone said. Just buy a hardware router that blocks out most ports and you'll be fine.