If you want to know more about port security go to the following link.
http://www.grc.com
click on the "Shields Up" logo, then scroll down to "Hot Spots", and click on the "Shields Up". This is a very excellent place to start with port security. You will find out where the leaks are at, whether it is open, failed, passed, or stealth, and how to secure them. Just take your time, browse, and enjoy the site. I have been using this site for many years, and have had a lot of success using it for other peoples pc's.
But TSG is the best for any kind of answer. I kinda stumbled on the site when I D/L'd Firefox. Being the Alpha-Geek-Nerd that I am, I decided to go through the whole add ons section, (recommend at least two days off). Then I found the add-on for TSG read a bit about them and then went to the site, liked what I saw and added the 'add-on',. Glad I did! Sorry about the long post, I do hope this gets you going.