FREE for personal use, Sygate Personal Firewall 4.0 is more than an advanced, user-friendly personal firewall -- it is a bi-directional intrusion defense system. In essence, Sygate Personal Firewall makes your protected machines invisible to the outside world. That makes Sygate Personal Firewall a must-have security measure for any PC that connects to a private network or the public Internet. If that isn't enough, Sygate Personal Firewall includes advanced active-scan vulnerability assessment to pinpoint your weaknesses and fine-tune your security policy. Sygate Personal Firewall is FREE for personal use and business licenses are $39.99.