This LFCS practice question tests your understanding of networking. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A system administrator is troubleshooting network connectivity from a Linux server to a remote host at 10.0.0.1. The server has a default gateway of 192.168.1.1. Running `ping 10.0.0.1` fails, but `ping 192.168.1.1` succeeds. The output of `ip route show` shows a default route via 192.168.1.1. Which additional step should the administrator take to further investigate?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Run traceroute to 10.0.0.1 to see where packets are dropped.
Option C is correct because the ping to the default gateway succeeds, confirming local network and ARP resolution are functional, while the ping to the remote host fails. Running traceroute to 10.0.0.1 will reveal the exact hop where packets are dropped, isolating whether the issue lies in routing beyond the gateway, a firewall along the path, or a missing route on an intermediate router.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Check the ARP table for 10.0.0.1.
Why it's wrong here
ARP is used for local subnet resolution; 10.0.0.1 is not local.
✗
Verify that the firewall on the remote host allows ICMP.
Why it's wrong here
This is a possible cause but not the first step; traceroute should be done first.
✓
Run traceroute to 10.0.0.1 to see where packets are dropped.
Why this is correct
Traceroute reveals the path and where packets stop, aiding in pinpointing the issue.
Related concept
Read the scenario before looking for a memorised answer.
✗
Check if the remote host is in the same subnet as the server.
Why it's wrong here
The IP addresses show they are on different subnets, so this is obvious.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume a failed ping to a remote host must be due to a local ARP issue or firewall on the destination, but the successful ping to the gateway proves local connectivity works, making traceroute the logical next step to trace the path.
Trap categories for this question
Command / output trap
The IP addresses show they are on different subnets, so this is obvious.
Detailed technical explanation
How to think about this question
Traceroute uses ICMP Time Exceeded messages (or UDP probes on Linux) to map the path; a sudden timeout after the gateway indicates a routing black hole or a firewall dropping packets at that hop. In real-world scenarios, a missing static route on the ISP router or an ACL blocking ICMP at an intermediate hop can cause this symptom, and traceroute pinpoints exactly where the failure occurs.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Networking — This question tests Networking — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Run traceroute to 10.0.0.1 to see where packets are dropped. — Option C is correct because the ping to the default gateway succeeds, confirming local network and ARP resolution are functional, while the ping to the remote host fails. Running traceroute to 10.0.0.1 will reveal the exact hop where packets are dropped, isolating whether the issue lies in routing beyond the gateway, a firewall along the path, or a missing route on an intermediate router.
What should I do if I get this LFCS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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