100-140 Question 216
Single answerA user reports that they are unable to access a specific website, but other websites are working fine. You use the 'traceroute' (or 'tracert' on Windows) command to troubleshoot the issue. The output shows that the trace completes several hops but then stops at a specific router, displaying asterisks (*) for subsequent hops. Based on this output, what could be the most likely cause of the issue?
- A
A firewall or security device is blocking traffic beyond the specified router.
- B
The user's local network connection is down.
- C
The website's server is offline.
- D
The traceroute command is not supported on the user's operating system.
Show answer and explanation
Correct answer: A
Explanation
In this scenario, the traceroute output shows that the packets successfully reach a specific router but are unable to progress beyond that point. This behavior typically suggests that a firewall or security device at that router or beyond is blocking the traffic, such as ICMP packets used by traceroute. The other options do not align with the described output of the traceroute command.
- A. Correct.
If traceroute reaches a specific router and then shows asterisks (*) for subsequent hops, it typically indicates that a firewall or security device is blocking ICMP traffic or other protocols used by traceroute, preventing further trace progress.
- B. Incorrect.
If the user's local network connection were down, traceroute would not have been able to complete any hops at all, as it would fail to reach even the first router.
- C. Incorrect.
If the website's server were offline, traceroute would likely still complete all intermediate hops but fail to reach the final destination. It would not stop at a specific router.
- D. Incorrect.
Traceroute is a widely supported command on most modern operating systems. If it were unsupported, the command would not run at all, rather than partially completing.