What is a “FIREWALL”
The main goal of a personal firewall is to protect your personal computer and private network from malicious mischief. Malware, malicious software, is the primary threat to your home computer. Viruses are often the first type of malware that comes to mind. A virus can be transmitted to your computer through email or over the Internet and can quickly cause a lot of damage to your files. Other malware includes Trojan horse programs and spyware. These programs are usually designed to acquire your personal information for the purposes of identity theft of some kind. There are two ways a Firewall can prevent this from happening. It can allow all traffic to pass through except data that meets a predetermined set of criteria, or it can prohibit all traffic unless it meets a predetermined set of criteria.
Windows has a firewall built-in and turned on by default. However, some people prefer not to use the pre-built Microsoft version so in this case we recommend either Zone Alarm or Comodo. Both are FREE and work very well.