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.
Exhibit
Refer to the exhibit.
# ip route show
10.0.1.0/24 dev eth0 proto kernel scope link src 10.0.1.10
10.0.2.0/24 dev eth1 proto kernel scope link src 10.0.2.10
default via 10.0.1.1 dev eth0
A host with this routing table can ping 10.0.2.1 but cannot ping 8.8.8.8. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Refer to the exhibit.
# ip route show
10.0.1.0/24 dev eth0 proto kernel scope link src 10.0.1.10
10.0.2.0/24 dev eth1 proto kernel scope link src 10.0.2.10
default via 10.0.1.1 dev eth0
A
The default route is missing
Why wrong: The table shows a default route via 10.0.1.1.
B
The default gateway 10.0.1.1 does not have internet connectivity
Even though the host can reach the gateway, the gateway itself may not have a path to the internet.
C
The host has no route to 10.0.2.0/24
Why wrong: The table shows a direct route to 10.0.2.0/24 via eth1.
D
The host has no route to 10.0.1.1
Why wrong: The host has a direct route to 10.0.1.0/24, so it can reach 10.0.1.1.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The default gateway 10.0.1.1 does not have internet connectivity
The host can ping 10.0.2.1, which is on the directly connected 10.0.2.0/24 network, confirming that the local interface and link-layer are functional. However, it cannot ping 8.8.8.8, a public internet address. The routing table shows a default route via 10.0.1.1, so the host will forward the packet to that gateway. Since the host has a default route, the most likely cause is that the gateway 10.0.1.1 itself lacks internet connectivity (e.g., no upstream route, NAT misconfiguration, or ISP outage), preventing the packet from reaching 8.8.8.8.
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.
The default gateway 10.0.1.1 does not have internet connectivity
Why this is correct
Even though the host can reach the gateway, the gateway itself may not have a path to the internet.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The host has no route to 10.0.2.0/24
Why it's wrong here
The table shows a direct route to 10.0.2.0/24 via eth1.
✗
The host has no route to 10.0.1.1
Why it's wrong here
The host has a direct route to 10.0.1.0/24, so it can reach 10.0.1.1.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume a missing default route is the only cause for internet unreachability, but the question explicitly states the routing table includes a default route, shifting the focus to the gateway's own connectivity or upstream routing failure.
Trap categories for this question
Command / output trap
The table shows a default route via 10.0.1.1.
Detailed technical explanation
How to think about this question
When a host sends a packet to a non-local destination, it performs a longest-prefix match on its routing table and forwards the packet to the next-hop gateway. The gateway then performs its own routing decision; if it has no route to the destination or lacks internet connectivity (e.g., no NAT or upstream default route), the packet is dropped. This scenario highlights the difference between local link reachability (verified by pinging 10.0.2.1) and end-to-end path availability, which depends on the gateway's routing table and external connectivity. Tools like traceroute can isolate where the path breaks, and checking the gateway's routing table with 'ip route' or 'show ip route' on a router would confirm the missing upstream route.
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: The default gateway 10.0.1.1 does not have internet connectivity — The host can ping 10.0.2.1, which is on the directly connected 10.0.2.0/24 network, confirming that the local interface and link-layer are functional. However, it cannot ping 8.8.8.8, a public internet address. The routing table shows a default route via 10.0.1.1, so the host will forward the packet to that gateway. Since the host has a default route, the most likely cause is that the gateway 10.0.1.1 itself lacks internet connectivity (e.g., no upstream route, NAT misconfiguration, or ISP outage), preventing the packet from reaching 8.8.8.8.
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.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This LFCS practice question is part of Courseiva's free Linux Foundation certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the LFCS exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.