What is the primary function of a firewall?

The primary function of a firewall is to monitor and control incoming and outgoing network traffic based on predetermined security rules. This involves inspecting data packets as they enter or exit a network and determining whether to allow or block the traffic based on established policies. Firewalls serve as a critical line of defense in cybersecurity, acting as a barrier between trusted networks and untrusted ones, such as the internet.

By defining rules regarding which types of traffic can enter or leave the network, firewalls help in protecting sensitive information and preventing unauthorized access. They can also be configured to filter traffic according to specific criteria, such as IP address, port number, and protocol. This capability makes firewalls essential for maintaining the security and integrity of networked communications.

Other options, while related to security, do not capture the fundamental role of a firewall in network protection. Monitoring user access to applications or physically securing equipment involves different security mechanisms beyond the scope of what a firewall typically addresses.