I have a home network of 4 computers. I don't have a static IP, mine is dynamic but the ZoneAlarm is excellent software and it is free. Make sure you have your network set up for internal and external IP addresses. Within Zonealarm make sure you set it up to allow the local IP addresses to access your file and print sharing. If the system set up properly, it is very secure. Zonealarm will tell you if someone is trying access your computer. That and the hardware firewall should be very secure.