220-1101 Hardware and Network Troubleshooting Practice Question
A technician installs a new Gigabit Ethernet NIC in a workstation to replace a faulty onboard NIC. After installation, the technician connects the Ethernet cable from the switch to the new NIC. The link light on the new NIC is off. The technician swaps the cable with a known-good cable, but the light remains off. The new NIC is detected in Device Manager with no errors. The technician tries the new NIC in another workstation and it works fine. Which of the following should the technician do NEXT?
⚠ Common exam trap
It's easy for candidates to assume a hardware failure (NIC or cable) because the link light is off, overlooking the possibility that the switch port itself has been administratively disabled or placed in an error-disable state by a security or STP feature.
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 switch port configuration for port security or error-disable state
Since the NIC works in another workstation and a known-good cable doesn't resolve the issue, the problem is isolated to the switch port. Port security violations or error-disable states (e.g., from spanning-tree BPDU guard, UDLD, or a duplex mismatch) can administratively shut down the port, turning off the link light. Checking the switch port configuration is the logical next step to identify and clear such a condition.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Replace the switch
Why it's wrong here
Replacing the switch is an extreme, costly measure that ignores the evidence. The switch is presumably functioning for other devices on the network, and the problem is isolated to the single port connected to the new NIC. This points to a port-level issue such as an errdisable state, port security violation, or a configuration mismatch, not a hardware failure of the entire switch. Swapping the switch would disrupt the network and leave the underlying port issue unresolved.
- ✓
Check the switch port configuration for port security or error-disable state
Why this is correct
Port security features can cause a port to be error-disabled when a MAC address violation occurs, such as when a new NIC with an unknown MAC is connected. Checking the switch's interface status and resetting the port if needed will likely restore connectivity.
- ✗
Update the NIC driver to the latest version
Why it's wrong here
The NIC is detected in Device Manager without errors, indicating the driver is functioning. A driver issue would not typically cause the link light to be off; it would more likely cause connectivity problems after the link is established.
- ✗
Change the NIC's duplex setting in Windows
Why it's wrong here
You cannot configure duplex settings in Windows until a link is established, because the NIC driver exposes these properties only when the media is connected. Even if duplex could be set, a mismatch typically produces a link light that is on but with CRC errors and excessive collisions, not a completely dark link LED. The absence of a link light indicates the physical layer is down, so the cause is more likely a port security/error-disable state, cabling fault, or incorrect VLAN assignment, not a duplex negotiation problem.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 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 220-1101 exam.