A firewall is an essential piece of software for any PC connected to the internet, it stops hackers and malicious software from attacking your computer, causing damage or obtaining private information. A firewall runs in the background and monitors the data flowing between your PC and the internet, blocking anything that looks suspicious and warning you of potential dangers if some software (such as spyware or a virus) is trying to access the internet without permission.
ZoneAlarm is not an open source application, but a free firewall provided by a company which offers a range of other security tools. It’s fairly basic, but it does the job well enough and it’s not limited or restricted in any way and it doesn’t nag you to upgrade or buy anything, so we think it deserves to be included on this site. It’s easy to install and set up, and runs quietly and unobtrusively in the background without any problems or hassles. If your PC is not currently protected by any sort of firewall, we recommend you download a copy immediately: www.zonealarm.com