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 they can access websites by IP address but not by domain name. Based on the exhibit, 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
✓
Incorrect or unreachable DNS server
The user can access websites by IP address but not by domain name, which indicates that IP routing and connectivity are functioning correctly. The failure to resolve domain names points directly to a DNS issue, such as an incorrect or unreachable DNS server. DNS translates human-readable domain names into IP addresses; without a working DNS server, name resolution fails while direct IP access remains unaffected.
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.
✗
Duplicate IP address on the network
Why it's wrong here
Duplicate IP would cause intermittent issues, not just name resolution failure.
DNS is needed for name resolution; if it's down or wrong, domains won't resolve.
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.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse DNS failure with gateway or routing issues, but the ability to access sites by IP address proves that routing and gateway settings are correct, isolating the problem to name resolution.
Detailed technical explanation
How to think about this question
DNS resolution typically uses UDP port 53 for queries and TCP port 53 for zone transfers or large responses. When a DNS server is unreachable, the client's resolver will fail with a 'server not found' error after timeout, while cached entries or direct IP access remain unaffected. In Windows, the `nslookup` or `ping -a` command can isolate DNS issues, and the `ipconfig /displaydns` command shows cached DNS records.
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 network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
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: Incorrect or unreachable DNS server — The user can access websites by IP address but not by domain name, which indicates that IP routing and connectivity are functioning correctly. The failure to resolve domain names points directly to a DNS issue, such as an incorrect or unreachable DNS server. DNS translates human-readable domain names into IP addresses; without a working DNS server, name resolution fails while direct IP access remains unaffected.
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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This FC0-U61 practice question is part of Courseiva's free CompTIA 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 FC0-U61 exam.
Question Discussion
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