Question 26 of 464
N10-009 Local subnet communication Practice Question
A user reports that they cannot connect to a file server on the same subnet. The technician checks the workstation's IP configuration: IP 192.168.1.10, subnet mask 255.255.255.0, default gateway 192.168.1.1. The workstation can ping the gateway but cannot ping the file server at 192.168.1.50. Which of the following is the most likely cause?
⚠ Common exam trap
Test-takers frequently assume a failed ping means a network connectivity issue, but CompTIA often tests that a host firewall can block ICMP while allowing other traffic, so a ping failure does not necessarily indicate a broken path.
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
✓
The file server is powered off or disconnected from the network
The workstation can ping the gateway (192.168.1.1) but not the file server (192.168.1.50) on the same subnet. Since both are on the same subnet, the default gateway is not needed for local traffic. The inability to ping the server suggests the server itself is not responding. The most likely causes are that the server is powered off, its network cable is disconnected, or it has a failed network interface. A firewall blocking ICMP would also prevent ping, but the question specifies that the correct answer is the server being powered off or disconnected (option C). Therefore, the most likely cause is that the file server is powered off or has a disconnected cable.
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 subnet mask on the workstation
Why it's wrong here
Incorrect subnet mask would cause the workstation to incorrectly determine whether the server is on the same subnet; however, since the workstation can ping the gateway, the subnet mask is likely correct. If it were incorrect, pinging the gateway might still work if the gateway is on the same network as perceived by the workstation.
When this WOULD be correct
If the question described a scenario where the workstation's subnet mask was mismatched (e.g., 255.255.255.0 vs 255.255.0.0) and the file server was on a different subnet, then an incorrect subnet mask would be the correct answer.
- ✗
Incorrect default gateway on the workstation
Why it's wrong here
The default gateway is correctly configured because the workstation can ping it.
When this WOULD be correct
In a scenario where a workstation cannot reach any external networks (e.g., internet) but can ping local devices, the default gateway being misconfigured or down would be the correct answer. For example, if the workstation had IP 192.168.1.10/24 and could ping 192.168.1.50 but not 8.8.8.8, a wrong default gateway would be the cause.
- ✓
The file server is powered off or disconnected from the network
Why this is correct
The server being powered off or having its network cable disconnected would cause all traffic to fail, matching the symptoms.
- ✗
A firewall on the workstation is blocking traffic to the server
Why it's wrong here
A firewall on the workstation could block ICMP (ping) traffic to the server while allowing other traffic, but this is less likely than the server being offline or disconnected, especially since the user cannot connect to the file server (not just ping).
When this WOULD be correct
In a scenario where the workstation has an APIPA address (169.254.x.x) due to DHCP failure, and the question asks for the most likely cause, 'DHCP server unavailable' would be correct.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The N10-009 exam frequently reuses these exact scenarios with slightly different constraints.
✓The file server is powered off or disconnected from the networkCorrect answer▾
Why this is correct
The server being powered off or having its network cable disconnected would cause all traffic to fail, matching the symptoms.
✗Incorrect subnet mask on the workstationWrong answer — click to see why▾
Why this is wrong here
Option A is not defined, but if it were a common distractor like 'incorrect subnet mask,' the subnet mask 255.255.255.0 is correct for the given IPs on the same subnet, so it would not cause connectivity issues between them.
★ When this WOULD be the correct answer
If the question described a scenario where the workstation's subnet mask was mismatched (e.g., 255.255.255.0 vs 255.255.0.0) and the file server was on a different subnet, then an incorrect subnet mask would be the correct answer.
Why candidates choose this
Candidates may incorrectly assume that any connectivity problem is due to subnet mask misconfiguration, especially when they see IPs in the same range but overlook that the mask is actually correct.
✗Incorrect default gateway on the workstationWrong answer — click to see why▾
Why this is wrong here
The workstation can ping the gateway (192.168.1.1) but not the file server (192.168.1.50) on the same subnet. Since both are on the same subnet, the default gateway is not needed for local communication; the issue is likely with the file server itself or a local firewall, not the gateway.
★ When this WOULD be the correct answer
In a scenario where a workstation cannot reach any external networks (e.g., internet) but can ping local devices, the default gateway being misconfigured or down would be the correct answer. For example, if the workstation had IP 192.168.1.10/24 and could ping 192.168.1.50 but not 8.8.8.8, a wrong default gateway would be the cause.
Why candidates choose this
Candidates may assume that since the gateway is reachable, it must be correct, and then incorrectly attribute the problem to the gateway when the real issue is local connectivity. They might also confuse the role of the gateway in local vs. remote communication.
✗A firewall on the workstation is blocking traffic to the serverWrong answer — click to see why▾
Why this is wrong here
Option D is not provided in the question, so it cannot be evaluated. The correct answer is C, which is undefined in the given context.
★ When this WOULD be the correct answer
In a scenario where the workstation has an APIPA address (169.254.x.x) due to DHCP failure, and the question asks for the most likely cause, 'DHCP server unavailable' would be correct.
Why candidates choose this
Candidates might choose an undefined option out of confusion or misreading, especially if they expect a specific answer like 'firewall blocking' or 'incorrect subnet mask'.
Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
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Last reviewed: Jun 30, 2026
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