200-301 Question 8
Single answerA network administrator is configuring a router to enable communication between two separate LANs: 192.168.1.0/24 and 192.168.2.0/24. The administrator has already assigned the following IP addresses to the router's interfaces: 192.168.1.1/24 and 192.168.2.1/24. However, the devices on the two LANs cannot communicate with each other. What could be the most likely reason for this issue?
- A
The router's interfaces are not enabled.
- B
The wrong IP addresses were configured on the router interfaces.
- C
The devices on the LANs do not have the router's interface as their default gateway.
- D
The router is missing a static route to the other LAN.
Show answer and explanation
Correct answer: C
Explanation
For communication between two separate LANs through a router, devices must be configured to use the router's interface IP address as their default gateway. This ensures that traffic destined for a different subnet is forwarded to the router for routing. Without the correct default gateway configuration, devices cannot route traffic beyond their local subnet.
- A. Incorrect.
If the router's interfaces were not enabled, no communication would be possible. However, the scenario implies that the interfaces are configured, so this is unlikely.
- B. Incorrect.
The IP addresses configured on the router interfaces match the LANs' subnet ranges, so this is not the issue.
- C. Correct.
Devices on each LAN must use the router's respective interface IP address (192.168.1.1 for LAN 1 and 192.168.2.1 for LAN 2) as their default gateway to route traffic to the other LAN. If this is not set, devices cannot communicate outside their local subnet.
- D. Incorrect.
A static route is not required in this scenario because the router already has directly connected routes for both subnets. The issue lies elsewhere.