This FC0-U61 practice question tests your understanding of infrastructure. 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 user reports that their computer cannot access the internet, but it can reach other devices on the local network. Which of the following 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
✓
Misconfigured default gateway
The default gateway is the router interface that connects the local network to external networks, such as the internet. If the default gateway is misconfigured (e.g., wrong IP address or subnet mask), the computer can still communicate with devices on the same subnet using ARP and Layer 2 switching, but it cannot route packets to external destinations because it has no valid next-hop address. This directly explains why local access works but internet access fails.
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.
✗
Incorrect DNS server address
Why it's wrong here
DNS issues affect name resolution, but direct IP access might still work.
✗
Faulty network cable
Why it's wrong here
A faulty cable would typically prevent all network communication.
✓
Misconfigured default gateway
Why this is correct
Default gateway routes traffic outside the local subnet; a misconfiguration blocks internet access.
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.
✗
Local firewall blocking all outbound traffic
Why it's wrong here
A firewall blocking all outbound would also block local traffic in most cases.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse DNS issues with routing issues, assuming that 'cannot access the internet' automatically means DNS is broken, but the key clue is that local network access still works, which isolates the problem to Layer 3 routing (default gateway) rather than Layer 2 or application-layer issues.
Detailed technical explanation
How to think about this question
When a host sends a packet to a destination outside its subnet, it checks its routing table for a default route (0.0.0.0/0) pointing to the default gateway. If that gateway IP is unreachable or misconfigured (e.g., a non-existent router), the host will attempt ARP for the gateway but fail, or the gateway itself may not forward packets. In IPv4, the default gateway is typically the first usable address in the subnet (e.g., 192.168.1.1), and a common misconfiguration is setting it to an IP outside the local subnet, causing the host to treat it as unreachable.
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.
Infrastructure — This question tests Infrastructure — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Misconfigured default gateway — The default gateway is the router interface that connects the local network to external networks, such as the internet. If the default gateway is misconfigured (e.g., wrong IP address or subnet mask), the computer can still communicate with devices on the same subnet using ARP and Layer 2 switching, but it cannot route packets to external destinations because it has no valid next-hop address. This directly explains why local access works but internet access fails.
What should I do if I get this FC0-U61 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.
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Question Discussion
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