Many programs on your computer are designed to easily exchange information online. Without a firewall, anyone online can connect to these programs and use them to access information on your computer or network. Some of these programs may not contain much personal information, but some may contain security vulnerabilities that allow programs that contain personal information to access them.

Firewall is software that adds an extra layer of security to your computer. It is generally used to prevent unauthorized users from accessing your systems. It allows you to freely transmit information, but controls the incoming data using the security rules you set. Traffic that does not comply with these rules will be rejected. This reduces the amount of unwanted traffic, freeing up more resources for the desired data communication to occur.

Firewalls use predefined rules to analyze incoming traffic. They filter the traffic according to these rules. Therefore, it blocks unwanted, unknown or suspicious incoming communication. Analysis is performed at the main entrance of a network and at ports where exchange with external devices takes place.