A firewall is a security system that is used when a computer is connected to a network. The use of firewalls is primarily for keeping computers save from intruders and protecting it against malicious network traffic. It regulates traffic into and out of the user’s computer, either allowing valid data, or blocking unwanted access based on a predetermined set of security rules. A firewall establishes a barrier between secure internal networks and outside networks that might not be secure. Although firewalls have its purpose, it should never be the only safety measure in place as computer systems have many points of entry.