A firewall is a network security system that monitors and controls the incoming and outgoing network traffic based on predetermined rules, thereby protecting the computer from unauthorized access, damage to data, software or hardware. It is commonly used by businesses to protect company networks from various cyber threats. A firewall is a network security system that controls the incoming and outgoing flows of information in order to prevent unallowed access, unwanted intrusion, and other types of unauthorized data. They work by inspecting each packet of data coming into the computer and comparing it against a set of rules. There are many different rules that determine whether a packet is ‘allowed in’ or blocked in a firewall. For example, If the packet is part of an inbound connection, the firewall will block it from passing over to the protected area if it doesn’t have an explicit rule that explicitly allows inbound connections to reach the protected area.