Which device is commonly used to enforce security policies between networks?

• A. Router
• B. Switch
• C. Firewall
• D. Wireless Access Point

Answer: (C)

Enforcing security policies between networks is the job of a firewall. It sits at the boundary between networks and applies rules that decide which traffic is allowed or blocked as it crosses from one network segment to another. By inspecting traffic against policies based on factors like source and destination IPs, ports, protocols, and state information, a firewall creates a controlled barrier that prevents unauthorized access while permitting legitimate communication. Modern firewalls add features such as stateful inspection, application-level filtering, intrusion prevention, and VPN termination to strengthen policy enforcement and visibility.

A router’s primary purpose is routing packets to their destinations; while it can apply basic access control lists, it doesn’t provide the same depth of policy enforcement across networks. A switch focuses on forwarding frames and segmenting networks (often with VLANs) rather than policing traffic between networks. A wireless access point mainly provides wireless connectivity and, though it can include some security features, its main role is not enforcing cross-network security policies.