Gibson Research Corporation supplies a series of tests to test your firewall. My Zone Alarm Free passed with flying colours

http://www.grc.com/x/ne.dll?rh1dkyd2

That's a well respected test razz, and may be new to many of the newer members.

Yes, the GRC site has been around for some time and well respected as you say. If anyone is interested Steve Gibson appears on a weekly radio show that discuss important issues of personal computer security. The following link has a list of all the episodes in various formats, both audio and print versions. Some interesting reading and/or listening.
http://www.grc.com/securitynow.htm

Now that's new to me. Nice link squire. Bookmarked.

While I still use the GRC.com tests, I also like the PC Flank tests.

It's a good idea to remember that all fails are not necessarily so. The Shield Up test may have just been testing your router and not your computer. The data sent for the test may not have even reached your computer but instead been sent back by the router which Shields Up would interpret as a fail when in fact it's a great result for you.

An explanation on this here

http://onlinearmorpersonalfirewall.blogspo...ds-up-test.html

In my case the Sheilds Up test results indicate that all my ports are in stealth mode, not just closed. To me this would indicate that it was indeed Zone Alarm doing its job.