- A
Application layer (Layer 7)
Correct. The web service (HTTP) is an Application layer protocol. If the service is not running or misconfigured, the client cannot access the web page despite lower-layer connectivity.
- B
Session layer (Layer 5)
Why wrong: The Session layer manages sessions, but HTTP is an Application layer protocol. Session issues are less likely given successful lower-layer communication.
- C
Transport layer (Layer 4)
Why wrong: Since the firewall allows HTTP traffic, a Transport layer block is unlikely. If it were a port issue, ping would still work, but the symptom would be consistent with a firewall block. However, the most likely cause is the Application layer.
- D
Network layer (Layer 3)
Why wrong: Successful ping confirms that the Network layer (IP addressing and routing) is functioning correctly. The problem is at a higher layer.
Quick Answer
The answer is the Application layer (Layer 7). This is correct because a successful ping to the web server’s IP address confirms that Layers 1 through 3 (Physical, Data Link, Network) and Layer 4 (Transport) are functioning properly, since ICMP operates at the Network layer and relies on IP connectivity. The failure to load a web page, despite firewall rules permitting HTTP traffic, isolates the problem to Layer 7, where the HTTP protocol and web server software operate—common causes include a misconfigured document root, a missing Host header, or an application-layer authentication failure. On the CompTIA Network+ N10-009 exam, this scenario tests your ability to map symptoms to OSI layers, often using a ping success to rule out lower-layer issues while an application layer issue causing web page failure points upward. A common trap is assuming the problem is at the Transport layer (Layer 4) because HTTP uses TCP, but remember: ping uses ICMP, not TCP, so a successful ping does not verify HTTP functionality. Memory tip: “Ping works, page fails? Think Layer 7—the app’s the one that wails.”
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 technician is troubleshooting a connectivity issue. The technician can successfully ping the IP address of a web server (10.10.10.10) from a client, but the client cannot access the web page. Firewall rules allow HTTP traffic. At which OSI layer is the issue most likely occurring?
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 choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Application layer (Layer 7)
Since the client can successfully ping the web server's IP address (10.10.10.10), Layer 3 (Network) and Layer 4 (Transport) connectivity is verified, as ICMP operates at Layer 3 and uses IP. The failure to access the web page despite firewall rules allowing HTTP traffic points to an issue at Layer 7 (Application), such as a misconfigured web server (e.g., HTTP 404, incorrect document root), a missing or incorrect Host header in the HTTP request, or an application-layer proxy or authentication problem that prevents the HTTP transaction from completing.
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.
- ✓
Application layer (Layer 7)
Why this is correct
Correct. The web service (HTTP) is an Application layer protocol. If the service is not running or misconfigured, the client cannot access the web page despite lower-layer connectivity.
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.
- ✗
Session layer (Layer 5)
Why it's wrong here
The Session layer manages sessions, but HTTP is an Application layer protocol. Session issues are less likely given successful lower-layer communication.
- ✗
Transport layer (Layer 4)
- ✗
Network layer (Layer 3)
Why it's wrong here
Successful ping confirms that the Network layer (IP addressing and routing) is functioning correctly. The problem is at a higher layer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume that because ping works and firewall rules allow HTTP, the issue must be at the Transport layer (e.g., a blocked port), but the question specifically states the firewall allows HTTP, so the failure is at the Application layer where the web server fails to serve the page correctly.
Detailed technical explanation
How to think about this question
Under the hood, HTTP/1.1 requires a valid Host header in the request; if the web server is configured for a specific virtual host and the client sends a different or missing Host header, the server may respond with a 400 Bad Request or serve a default page that fails to load. Additionally, application-layer issues can involve TLS handshake failures (if HTTPS is expected but HTTP is used), HTTP redirect loops, or server-side scripting errors that return empty responses—all of which occur at Layer 7 and are invisible to lower-layer connectivity tests like ping.
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 practitioner preparing for the N10-009 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
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.
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Network Troubleshooting — study guide chapter
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FAQ
Questions learners often ask
What does this N10-009 question test?
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: Application layer (Layer 7) — Since the client can successfully ping the web server's IP address (10.10.10.10), Layer 3 (Network) and Layer 4 (Transport) connectivity is verified, as ICMP operates at Layer 3 and uses IP. The failure to access the web page despite firewall rules allowing HTTP traffic points to an issue at Layer 7 (Application), such as a misconfigured web server (e.g., HTTP 404, incorrect document root), a missing or incorrect Host header in the HTTP request, or an application-layer proxy or authentication problem that prevents the HTTP transaction from completing.
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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Last reviewed: Jun 11, 2026
This N10-009 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 N10-009 exam.
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