Actually I've been testing Zonealarm for quite a while in combination of different Windows versions and in combination with other software, like McAfee, Norton, Ad-Aware, TrackZapper and some more.
And if you are not using a hardware firewall, Zonealarm is a good replacement, both the free version and the Pro version.
The pro version has only a few additional things, like you can see, when the IP addres should be located, os someone who tries to intrude your pc.
And there are some other minor differences. But for a standard user the free version works very well.
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