The answer is that the gateway 10.0.0.1 is not configured to forward traffic to the internet, likely lacking NAT or an upstream route. Even with a correct default gateway in the routing table, as confirmed by `ip route show`, the server can send packets to the gateway, but if that gateway itself has no path or translation rule to reach external networks like 8.8.8.8, those packets are simply dropped. On the LFCS exam, this scenario tests your ability to distinguish between a client-side routing misconfiguration and a gateway-side forwarding failure—a common trap where candidates assume a visible default gateway guarantees internet access. Remember that a default gateway is only a next-hop; it must also be a router capable of forwarding beyond its own subnet. Memory tip: "Default gateway present? Check if the gateway itself has a route out."
LFCS Networking Practice Question
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 server that can reach internal resources but cannot access the internet. The server's /etc/sysconfig/network-scripts/ifcfg-eth0 file contains: BOOTPROTO=static, IPADDR=10.0.0.10, NETMASK=255.255.255.0, GATEWAY=10.0.0.1. The administrator runs 'ip route show' and sees: default via 10.0.0.1 dev eth0. However, 'ping 8.8.8.8' fails. Which 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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The gateway 10.0.0.1 is not configured to forward traffic to the internet (no NAT or upstream route).
The routing table shows a default gateway (10.0.0.1) is present, so the issue is not a missing route. Since the server can reach internal resources but not the internet, the most likely cause is that the gateway itself (10.0.0.1) is not configured to perform NAT or does not have an upstream route to forward traffic beyond the local subnet. Without this, packets destined for 8.8.8.8 are sent to the gateway but are then dropped because the gateway has no path to the internet.
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 is missing from the routing table.
The gateway 10.0.0.1 is not configured to forward traffic to the internet (no NAT or upstream route).
Why this is correct
The private IP gateway cannot route to the internet without NAT or a public IP.
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.
✗
DNS resolution is not configured.
Why it's wrong here
DNS is not required for pinging an IP address directly.
✗
A firewall is blocking outbound ICMP traffic.
Why it's wrong here
There is no evidence of a firewall; the issue is more fundamental.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume a missing default gateway is the problem when ping fails, but the question explicitly shows the default route exists, so the real issue is the gateway's inability to forward traffic beyond the local network.
Trap categories for this question
Command / output trap
The default route is present, as shown.
Detailed technical explanation
How to think about this question
When a host sends a packet to an external IP, it forwards it to the default gateway based on the routing table. The gateway must then perform Network Address Translation (NAT) if it has a private IP (like 10.0.0.1) and route the packet to the internet via its own upstream interface. If the gateway lacks an internet-facing route or NAT is not configured, the packet is dropped at the gateway, resulting in a 'Destination Net Unreachable' or timeout. This is a common scenario in lab environments where a router or firewall is not properly configured for internet access.
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 gateway 10.0.0.1 is not configured to forward traffic to the internet (no NAT or upstream route). — The routing table shows a default gateway (10.0.0.1) is present, so the issue is not a missing route. Since the server can reach internal resources but not the internet, the most likely cause is that the gateway itself (10.0.0.1) is not configured to perform NAT or does not have an upstream route to forward traffic beyond the local subnet. Without this, packets destined for 8.8.8.8 are sent to the gateway but are then dropped because the gateway has no path to the internet.
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.