What function does a firewall serve?

A firewall plays a critical role in network security by monitoring and controlling incoming and outgoing network traffic based on predetermined security rules. Its primary purpose is to establish a barrier between a trusted internal network and untrusted external networks, such as the internet. By analyzing traffic, a firewall can block unauthorized access attempts, protect against malicious software, and prevent the exploitation of vulnerabilities within the network.

Unlike improving internet speed, creating backup copies of data, or managing user accounts, the primary function of a firewall is to enforce security policies and prevent unwanted or harmful traffic from passing through the network. This is crucial in safeguarding sensitive information and maintaining the overall integrity and security of an organization's digital assets. Therefore, option B accurately reflects the essential function of a firewall in network security management.