I tried Kerio briefly, but it produced all sorts of instability - lots of error message (like memory can't be read) on startup, and lots of programs that used to work, were crashing. Including some games, and Skype (instantaneous messaging program). I didn't wait for a week to uninstall it...

I also searched for Symantec, but it doesn't seem to be free, and, well, I would prefer a free program.

Now, I am trying a personal firewall (free) I had never heard about before, but which was highly rated on www.download com: filseclab.

So far, it works great.

Here is my personal evaluation of three free firewall products:

ZoneAlarm
Worked great for a while, but recently I had problems with several programs not being able to access the Internet, despite the fact that apparently, they had full permissions.

Then, there are the serious doubts about its spyware status.

Kerio
The instability it produced on my computer made it unusable. Of course, results may vary for other computers.

Filseclab
Just using it for a few hours - will write an update if my opinion changes radically.

So far, it works great; I didn't have problems accessing the Internet with any program. Just like ZoneAlarm, it asks for permission for new programs - but unlike the free edition of ZoneAlarm, it seems to already include a database of known programs (both good and bad).

This program is completely free (it seems that it gets revenue from some advertisements on its "status" page); and it works great. Let's just hope that it doesn't also include some hidden surprises, like spyware.

>Hi Juan (and all).
>
>Thought you might be interested to know that after using Kerio for about a week I found three things that bothered me: (1) Kerio's web filtering routines are generally slower than ZA especially if the page being loaded is large. These are the routines that intercept and look for and try to stop pop up windows, ads, and so forth. (2) Kerio does not have an integrated browser cache cleaner like ZA where you can choose to save certain cookie files and clean other stuff up. A feature which I like to use regularly. (3) I have experienced problems loading and/or refreshing certain web pages. Several versions ago ZA had similar problems but they seem to have mostly resolved them as newer versions came out.
>
>On the positive side I do find the Kerio software has an easier look and feel user interface. I like the way it works. It has some nice features as well. It does not appear to phone home :)
>
>On balance however, the features I like in ZA are enough for me to stay with ZA for now. Just an fyi :)