ITPEC IP April 2025 Question 30
Three (3) PCs and an Internet-capable TV (television) set are to be connected to the Internet by using a hub and a router that has a firewall function. Which of the following is an appropriate connection that enables the firewall function of the router to be used for all the traffic between the devices and the Internet? Here, “FW” in each figure indicates the firewall function.
Explanation
All PCs and the TV on the router's LAN side, the Internet alone on its WAN side — then every path to the Internet crosses the firewall.
Traffic passes the firewall only when it goes from the LAN side of the router to the WAN side. In option (a) the three PCs reach a LAN port through the hub, the TV is on another LAN port, and the WAN port is the router's only link to the Internet. Any traffic between a device and the Internet has to go LAN side → FW → WAN side. The hub merely adds ports to the protected LAN.
Answer (a)
Why not others:
- •(b) — the Internet is plugged straight into a LAN port, so the PCs reach it without the firewall; the TV sits on a hub on the WAN side
- •(c) — the third PC and the TV share a hub with the Internet line, outside the firewall
- •(d) — the LAN side is linked to the Internet through the hub, bypassing the firewall; the WAN port serves only the TV
Key rule: A firewall protects only what sits behind it: every internal device on the inside, and the firewall as the sole path to the outside.
Networks · AI-written, may contain errors
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