What is the function of a firewall?

A firewall serves as a critical security barrier for a network, designed specifically to protect against unauthorized access and various threats. Its main function is to monitor and control incoming and outgoing network traffic based on predetermined security rules. By establishing a protective perimeter, a firewall helps ensure that only authorized users and data packets can access the network, thus providing a safeguard against potential attacks, malware, and other cyber threats.

The other functions listed do not pertain to what a firewall does. Increasing device storage capacity relates to hardware upgrades or cloud storage solutions, enhancing internet speed pertains to improving connection quality or bandwidth management, and facilitating file sharing involves enabling collaborative work within a network rather than protection from external threats.