N10-009 Network Troubleshooting Practice Question
A user reports that they cannot access the internet. The user's workstation has an IP address of 192.168.1.100/24, with a default gateway of 192.168.1.1. The user can ping the default gateway but cannot ping 8.8.8.8. Other users on the same subnet can ping 8.8.8.8. The technician checks the switch and sees the user's port is up. What should the technician check next?
⚠ Common exam trap
The trap here is that candidates often jump to checking the router's routing table (Option A) or DNS (Option C) when the symptom is a ping failure to an IP address, but the key clue is that other users on the same subnet are unaffected, isolating the problem to the workstation's configuration.
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
✓
Check the workstation's IP configuration for a misconfigured default gateway or DNS
Since the user can ping the default gateway (192.168.1.1) but not 8.8.8.8, while other users on the same subnet can reach 8.8.8.8, the issue is isolated to this workstation. The most likely cause is a misconfigured default gateway (e.g., wrong IP or subnet mask) or DNS settings, as the gateway is reachable but traffic is not being forwarded correctly. Option B directly addresses checking the workstation's IP configuration for these misconfigurations, which is the logical next step after verifying local connectivity.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Check the router's routing table for a route to the internet
Why it's wrong here
If other users on the same network segment can successfully access the internet, it strongly indicates that the router's routing table is correctly configured to forward traffic to the internet. A problem with the router's global routing configuration would typically affect all connected devices, not just a single workstation. Therefore, the issue is more likely localized to the workstation's specific network settings rather than the shared network infrastructure.
When this WOULD be correct
If all users on the subnet cannot ping 8.8.8.8, but can ping the default gateway, then the router likely lacks a default route to the internet, making checking the routing table the correct next step.
- ✓
Check the workstation's IP configuration for a misconfigured default gateway or DNS
Why this is correct
The user can ping the gateway, so the gateway IP (192.168.1.1) is reachable. But if the gateway is not the correct router for internet access, or if the workstation has a local firewall blocking outbound traffic, internet access may fail.
- ✗
Check the DNS server configuration on the workstation
Why it's wrong here
Pinging an IP address like 8.8.8.8 directly bypasses the Domain Name System (DNS) resolution process entirely. DNS is only utilized when a user attempts to access a resource by its hostname (e.g., google.com), requiring translation to an IP address. Since the test uses a numerical IP, a misconfiguration of the workstation's DNS server would not prevent this specific ping from succeeding or failing, making it irrelevant to this particular diagnostic step.
When this WOULD be correct
A user reports they cannot access a website by name (e.g., www.example.com) but can ping 8.8.8.8. Other users can access the website. The workstation has correct IP and gateway settings. In this scenario, DNS misconfiguration is the likely cause.
- ✗
Check the switch port for VLAN misconfiguration
Why it's wrong here
A VLAN misconfiguration on the switch port would typically prevent the workstation from communicating with any devices outside its assigned (and incorrect) VLAN, including its intended default gateway. If the workstation could successfully ping its default gateway, it confirms that it is operating within the correct VLAN and can establish Layer 2 and Layer 3 connectivity to that gateway. Therefore, a VLAN issue is unlikely if local gateway reachability is confirmed.
When this WOULD be correct
A technician finds that all users on a specific switch port cannot access the internet, but other ports work. The switch port is up, but pinging the default gateway fails. In this scenario, checking for VLAN misconfiguration (e.g., port assigned to wrong VLAN) would be the next logical step.
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.
✓Check the workstation's IP configuration for a misconfigured default gateway or DNSCorrect answer▾
Why this is correct
The user can ping the gateway, so the gateway IP (192.168.1.1) is reachable. But if the gateway is not the correct router for internet access, or if the workstation has a local firewall blocking outbound traffic, internet access may fail.
✗Check the router's routing table for a route to the internetWrong answer — click to see why▾
Why this is wrong here
The user can ping the default gateway but not 8.8.8.8, while other users on the same subnet can. This indicates the router's internet routing is working; the issue is isolated to the workstation, not the router's routing table.
★ When this WOULD be the correct answer
If all users on the subnet cannot ping 8.8.8.8, but can ping the default gateway, then the router likely lacks a default route to the internet, making checking the routing table the correct next step.
Why candidates choose this
Candidates may assume internet access failure is always a routing problem, overlooking that the symptom is isolated to one workstation, which points to a local configuration issue.
✗Check the DNS server configuration on the workstationWrong answer — click to see why▾
Why this is wrong here
The user can ping the default gateway but not 8.8.8.8, indicating the issue is with routing beyond the local network, not DNS. DNS is irrelevant because the test uses an IP address (8.8.8.8), not a hostname.
★ When this WOULD be the correct answer
A user reports they cannot access a website by name (e.g., www.example.com) but can ping 8.8.8.8. Other users can access the website. The workstation has correct IP and gateway settings. In this scenario, DNS misconfiguration is the likely cause.
Why candidates choose this
Candidates often confuse internet access issues with DNS problems, especially when the symptom is 'cannot access the internet' without specifying whether it's by name or IP.
✗Check the switch port for VLAN misconfigurationWrong answer — click to see why▾
Why this is wrong here
The user can ping the default gateway but not 8.8.8.8, while other users on the same subnet can ping 8.8.8.8. This indicates the issue is isolated to the workstation, not a VLAN misconfiguration on the switch, which would affect all users in that VLAN.
★ When this WOULD be the correct answer
A technician finds that all users on a specific switch port cannot access the internet, but other ports work. The switch port is up, but pinging the default gateway fails. In this scenario, checking for VLAN misconfiguration (e.g., port assigned to wrong VLAN) would be the next logical step.
Why candidates choose this
Candidates may think that since the switch port is up but connectivity is broken, a VLAN mismatch could be the cause, overlooking that the issue is isolated to one workstation and the gateway is reachable.
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
Quick reference
IPv4 Address Class Summary
| Class | First Octet Range | Default Mask | Networks | Hosts per Network |
|---|---|---|---|---|
| A | 1–126 | /8 (255.0.0.0) | 126 | 16,777,214 |
| B | 128–191 | /16 (255.255.0.0) | 16,384 | 65,534 |
| C | 192–223 | /24 (255.255.255.0) | 2,097,152 | 254 |
| D | 224–239 | N/A | Multicast groups | — |
| E | 240–255 | N/A | Reserved / experimental | — |
127.x.x.x is reserved for loopback. Modern networks use CIDR (classless) rather than classful addressing.
Go deeper
Related to this question
Learn chapter
Troubleshoot: Network Connectivity
Key term
Switch
A switch is a networking device that connects devices on a local area network and uses MAC addresses to forward data only to the intended recipient.
Key term
CAN
A CAN (Controller Area Network) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other without a host computer.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.