200-301 Question 280
Select 3A network administrator has configured a static route on a router using the command ip route 192.168.10.0 255.255.255.0 10.1.1.2. However, the administrator notices that traffic to the 192.168.10.0/24 network is not being forwarded. After troubleshooting, it is discovered that the next-hop IP address (10.1.1.2) is unreachable. What could be the most likely reasons for this issue?
- A
There is no route in the routing table for the 10.1.1.2 next-hop.
- B
The interface connected to the next-hop 10.1.1.2 is administratively down.
- C
The static route was incorrectly configured with the wrong subnet mask for the destination network.
- D
A more specific route to 192.168.10.0/24 exists in the routing table, overriding the static route.
- E
Access control lists (ACLs) are blocking traffic to the 10.1.1.2 next-hop.
Show answer and explanation
Correct answers: A, B, E
Explanation
For a static route to function properly, the next-hop IP address must be reachable. If there is no route to the next-hop in the routing table, the interface to the next-hop is down, or ACLs are blocking traffic to the next-hop, the static route will fail. Therefore, options 1, 2, and 5 are correct. Options 3 and 4 do not directly address the issue of next-hop reachability.
- A. Correct.
If there is no route in the routing table to reach the next-hop 10.1.1.2, the static route cannot be used, as the router would not know how to forward traffic to the next-hop.
- B. Correct.
If the interface connected to the next-hop 10.1.1.2 is administratively down, the router cannot communicate with the next-hop, causing the static route to fail.
- C. Incorrect.
While an incorrect subnet mask for the destination network could cause routing issues, it does not explain why the next-hop is unreachable.
- D. Incorrect.
A more specific route in the routing table would override the static route, but it does not make the next-hop IP unreachable.
- E. Correct.
If ACLs are configured and block traffic to the next-hop 10.1.1.2, the router cannot establish communication with the next-hop, leading to the issue.