Which system filters traffic entering, passing through, or leaving the router?

Which system filters traffic entering, passing through, or leaving the router?

• A. Firewall
• B. NAT
• C. Mangle
• D. Queues

Answer: (A)

Filtering traffic at the router’s boundaries is handled by the firewall. In RouterOS, the firewall can apply rules to traffic entering the router (input), passing through it (forward), or leaving the router (output), letting you permit or drop packets based on criteria like source/destination IPs, ports, and protocol. NAT translates addresses for traffic as it traverses the router, which is separate from filtering. Mangle is used for marking packets for QoS or routing decisions, not for general filtering. Queues manage bandwidth and scheduling, not filtering. So the firewall is the component designed to filter traffic in all three directions.

Filtering traffic at the router’s boundaries is handled by the firewall. In RouterOS, the firewall can apply rules to traffic entering the router (input), passing through it (forward), or leaving the router (output), letting you permit or drop packets based on criteria like source/destination IPs, ports, and protocol. NAT translates addresses for traffic as it traverses the router, which is separate from filtering. Mangle is used for marking packets for QoS or routing decisions, not for general filtering. Queues manage bandwidth and scheduling, not filtering. So the firewall is the component designed to filter traffic in all three directions.