Which term describes a device that monitors and controls incoming and outgoing traffic?

• A. Firewall
• B. Router
• C. Switch
• D. Intrusion Detection System

Answer: (A)

Firewall. It’s the device that monitors and controls incoming and outgoing traffic by enforcing security rules. Positioned at the network edge or on a host, it filters traffic based on criteria like IP addresses, ports, and protocols, and can perform more advanced checks such as stateful inspection or application-layer filtering to permit legitimate communications while blocking threats. Routers direct traffic between networks but don’t enforce security policies in the same way; switches move frames within a LAN; IDS systems detect suspicious activity and alert, and may block only in Integrated IPS deployments.