What is the primary function of a firewall in a computer network?

• A. Encrypts data in transit.
• B. Stores user credentials.
• C. Monitors and controls incoming/outgoing network traffic based on rules.
• D. Schedules CPU tasks for processes.

Answer: (C)

Firewalls regulate traffic at the network boundary by monitoring and enforcing rules that determine which packets can pass between networks. They inspect both incoming and outgoing traffic and decide to permit or block data based on criteria such as source and destination IPs, ports, protocols, and the state of connections. This control is what helps prevent unauthorized access while allowing legitimate communication, like a user reaching a web server or a server replying to a request. Encrypting data in transit protects the contents of the communication, but that’s not the firewall’s primary job. Storing user credentials is about authentication data, not traffic control. Scheduling CPU tasks belongs to the operating system’s task management, not network security.