ShieldsUP! is a useful tool which collects no cookies and does no harm to your computer, but tests your internet connection to determine vulnerabilities (such as unshielded ports, etc.) The tests are free, you need not subscribe, they don't know who you are except that they do have your IP address and any information they can derive from that.
(You don't know what information is available from your IP address? Good reason to check it out. You don't know what your IP address is? I do. Go to the end of this website, scroll up half a screen, and check the little sign the danasoft.com mouse is holding up.)
It takes a while to run some of the tests, but in non-prime service hours I ran the full port test in 68 seconds. Result: all of my ports were found to be "stealthed", as opposed to "closed" or even (shudder) "open". That is, if someone tries to ping me the port pretends that I don't exist and doesn't even attempt to respond ... which some 'closed' ports may do.
My protection is from Norton Internet Security, a subscription service which I renew annually. It includes Norton Antivirus and Firewall protection. I recommend it highly, it's worth
You may not be interested in this, but it's a very Geek thing to do, don't you think?