Which of the following is a characteristic of a firewall?

A firewall is specifically designed to provide a layer of security by monitoring and controlling incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between a trusted internal network and untrusted external networks, effectively preventing unauthorized access to or from the network.

This function is critical in network security as it helps protect sensitive data and systems from potential threats and unauthorized access by filtering traffic and blocking malicious intrusions. The principles behind a firewall revolve around establishing a rule set that allows legitimate traffic while denying unauthorized attempts to enter or exit a network.

In contrast, while the other options may refer to functions relevant to different technologies or systems, they do not align with the primary purpose of a firewall, which is to enhance security through traffic management and regulation.