What is a firewall?

A firewall is a security system designed to monitor and control the incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between trusted internal networks and untrusted external networks, such as the internet. By analyzing data packets, a firewall can block harmful traffic or unauthorized access while allowing legitimate communication to pass through, thereby protecting a network or individual devices from cyber threats.

In contrast, a type of malware refers to malicious software intended to cause harm, which does not define the function of a firewall. An email filtering system specifically targets email traffic, attempting to filter out spam or malicious content, which is just one aspect of security technology. A data recovery tool is used to restore lost or corrupted files but does not provide the network-level protection that a firewall offers.