The answer is that the workstation is using the wrong DNS server address. This is the most likely cause because the client’s DNS server is misconfigured to point to 8.8.8.8, a public resolver that has no record for the internal domain intranet.company.com; only the internal DNS server at 10.0.0.10 hosts that zone. Since the user can ping the server’s IP address (10.0.0.50), network connectivity is intact, isolating the fault to name resolution. On the CompTIA Network+ N10-009 exam, this scenario tests your understanding of how client DNS server misconfiguration breaks internal name resolution while external internet access may still work—a common trap where technicians overlook the DNS server field in IPv4 settings. A quick memory tip: if you can ping the IP but not the FQDN, always check the DNS server address first.
N10-009 Network Troubleshooting Practice Question
This N10-009 practice question tests your understanding of network troubleshooting. 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 cannot access the internal web server by its fully qualified domain name (intranet.company.com). The workstation's IP configuration shows a DNS server of 8.8.8.8, but the internal DNS server is 10.0.0.10. The user can successfully ping the server's IP address (10.0.0.50). What is the MOST likely cause of the issue?
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.
A: The workstation is using the wrong DNS server address
The DNS server should be set to the internal DNS server to resolve internal hostnames.
B
B: The subnet mask on the workstation is incorrect
Why wrong: An incorrect subnet mask would affect communication within the local subnet, but ping to the server IP works, so this is not the issue.
C
C: The network cable is faulty
Why wrong: A faulty cable would cause connectivity issues entirely, but the user can ping the server IP, indicating the cable is functional.
D
D: The default gateway is misconfigured
Why wrong: If the default gateway were incorrect, the user would not be able to reach devices on other subnets, but ping to the server IP works, so the gateway is functioning.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A: The workstation is using the wrong DNS server address
The workstation's DNS server is set to 8.8.8.8 (a public Google DNS server), which cannot resolve the internal domain name 'intranet.company.com' because that zone is only hosted on the internal DNS server at 10.0.0.10. Since the user can ping the server's IP address (10.0.0.50), network connectivity is fine, confirming the issue is name resolution. The most likely cause is that the workstation is using the wrong DNS server address.
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.
✓
A: The workstation is using the wrong DNS server address
Why this is correct
The DNS server should be set to the internal DNS server to resolve internal hostnames.
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.
✗
B: The subnet mask on the workstation is incorrect
Why it's wrong here
An incorrect subnet mask would affect communication within the local subnet, but ping to the server IP works, so this is not the issue.
✗
C: The network cable is faulty
Why it's wrong here
A faulty cable would cause connectivity issues entirely, but the user can ping the server IP, indicating the cable is functional.
✗
D: The default gateway is misconfigured
Why it's wrong here
If the default gateway were incorrect, the user would not be able to reach devices on other subnets, but ping to the server IP works, so the gateway is functioning.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse a DNS resolution failure with a network connectivity issue, but the ability to ping the IP address proves the problem is strictly name resolution, not layer 2 or layer 3 problems.
Detailed technical explanation
How to think about this question
DNS resolution relies on the workstation sending a query to its configured DNS server; if that server does not have authority or forwarding for the internal zone, it returns a non-existent domain (NXDOMAIN) or fails to respond. In this scenario, the internal DNS server at 10.0.0.10 likely hosts a forward lookup zone for 'company.com' with an A record for 'intranet', while 8.8.8.8 has no such record. A common real-world fix is to configure the workstation's DNS to point to the internal DNS server, or to set up conditional forwarding on the public DNS server to the internal zone.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this N10-009 question in full detail.
Network Troubleshooting — This question tests Network Troubleshooting — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: A: The workstation is using the wrong DNS server address — The workstation's DNS server is set to 8.8.8.8 (a public Google DNS server), which cannot resolve the internal domain name 'intranet.company.com' because that zone is only hosted on the internal DNS server at 10.0.0.10. Since the user can ping the server's IP address (10.0.0.50), network connectivity is fine, confirming the issue is name resolution. The most likely cause is that the workstation is using the wrong DNS server address.
What should I do if I get this N10-009 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
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A user can access a website by its IP address (e.g., 203.0.113.5) but cannot access it by its domain name (example.com). Other users on the same subnet can access the website by domain name. Which of the following should the technician check FIRST?
medium
✓ A.A
B.B
C.C
D.D
Why A: The issue is isolated to a single user who can reach the website by IP but not by domain name, while other users on the same subnet have no problem. This points to a client-side DNS resolution failure, most likely a misconfigured or missing DNS server address in the user's network settings. The technician should first check the user's DNS configuration (e.g., `ipconfig /all` on Windows or `cat /etc/resolv.conf` on Linux) to ensure it points to a valid DNS server.
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Question Discussion
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