220-1101 Hardware and Network Troubleshooting Practice Question
A user reports that their desktop computer intermittently loses network connectivity for a few seconds at a time. The technician observes that the link light on the NIC turns off briefly and then back on. The technician has already replaced the Ethernet cable and the switch port. The issue persists. Which of the following should the technician check NEXT?
⚠ Common exam trap
The trap here is that candidates often jump to replacing the NIC (Option C) or updating drivers (Option A) when they see intermittent connectivity, overlooking that the link light behavior points to a physical-layer issue that environmental factors like EMI can cause even with known-good cables and ports.
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 for electromagnetic interference near the cable
The link light turning off indicates a physical layer issue, and since the cable and switch port have already been replaced, the next likely cause is electromagnetic interference (EMI) from nearby sources such as power cables, fluorescent lights, or large motors. EMI can corrupt the signal on unshielded twisted-pair (UTP) cabling, causing the NIC to momentarily lose link. Checking for and rerouting cables away from interference sources is the appropriate next step before replacing hardware.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Update the NIC driver
Why it's wrong here
Updating the NIC driver updates the software that controls the network adapter, which can fix packet loss, speed negotiation errors, or crashes related to driver bugs, but it cannot resolve physical-layer problems like electromagnetic interference. The scenario describes intermittent loss of network connectivity and a link light that likely drops, which indicates a Layer 1 issue; driver faults typically cause errors at Layer 2 or higher and are usually accompanied by error events in the OS, not a physically down link. While keeping drivers current is good practice, it should not be the first step when the symptom is a link that physically goes down, because no software update can shield a cable from external interference.
When this WOULD be correct
A user reports no network connectivity after a driver update. The link light is off constantly. In that scenario, updating or rolling back the NIC driver would be the correct next step.
- ✓
Check for electromagnetic interference near the cable
Why this is correct
Electromagnetic interference (EMI) from nearby power cables, electric motors, fluorescent lighting, or other high-current devices can induce noise on an unshielded Ethernet cable, causing intermittent link drops even when the cable and NIC are otherwise healthy. Verify that the network cable is not coiled alongside or run in parallel with AC power lines, and reroute or replace it with shielded twisted-pair (STP) cabling if interference is suspected. This aligns with the link light behavior, which typically flickers or drops during the interference events, pointing to a physical-layer (Layer 1) issue rather than a software or configuration problem.
- ✗
Replace the network interface card (NIC)
Why it's wrong here
Replacing the NIC is a more invasive and costly step that assumes the adapter hardware itself is faulty, but the intermittent nature of the drop—especially if it correlates with nearby electrical equipment—suggests an external environmental cause. A failing NIC generally produces consistent or worsening symptoms, such as a link that never establishes or dies completely, rather than a link that drops only under specific conditions. Before replacing hardware, troubleshoot and eliminate EMI as a cause; if the problem is electromagnetic interference, installing a new NIC will not fix it, and the replacement could even exhibit the same issue if the cable or environment is unchanged.
When this WOULD be correct
This would be correct if the technician had already verified no EMI, replaced the cable and switch port, and the NIC's link light remains off or the device fails to connect at all, indicating a faulty NIC.
- ✗
Configure the NIC to use a static IP address
Why it's wrong here
Assigning a static IP address changes only the network-layer (Layer 3) configuration, which controls addressing and routing, and has no effect on the physical link state or carrier signal. The symptom of intermittent connectivity with a link light that drops indicates the cable or connection itself is failing at Layer 1, independent of IP addressing. Even if DHCP lease renewal were somehow related to connectivity loss, that would not cause the physical link indicator to go dark; a static IP would also not stop electromagnetic interference from severing the carrier, so this option is irrelevant to the reported symptom.
When this WOULD be correct
A user reports intermittent connectivity but the link light remains on. The technician finds the IP address is obtained via DHCP and suspects a DHCP server issue or IP address conflict. In that scenario, configuring a static IP would be a valid next step to rule out DHCP problems.
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 220-1101 exam frequently reuses these exact scenarios with slightly different constraints.
✓Check for electromagnetic interference near the cableCorrect answer▾
Why this is correct
Electromagnetic interference (EMI) from nearby power cables, electric motors, fluorescent lighting, or other high-current devices can induce noise on an unshielded Ethernet cable, causing intermittent link drops even when the cable and NIC are otherwise healthy. Verify that the network cable is not coiled alongside or run in parallel with AC power lines, and reroute or replace it with shielded twisted-pair (STP) cabling if interference is suspected. This aligns with the link light behavior, which typically flickers or drops during the interference events, pointing to a physical-layer (Layer 1) issue rather than a software or configuration problem.
✗Update the NIC driverWrong answer — click to see why▾
Why this is wrong here
The technician has already replaced the Ethernet cable and switch port, ruling out physical layer issues. Intermittent link light behavior points to external interference, not driver issues.
★ When this WOULD be the correct answer
A user reports no network connectivity after a driver update. The link light is off constantly. In that scenario, updating or rolling back the NIC driver would be the correct next step.
Why candidates choose this
Candidates often default to driver updates for intermittent issues, but here the link light behavior indicates a physical layer problem, not a software one.
✗Replace the network interface card (NIC)Wrong answer — click to see why▾
Why this is wrong here
Replacing the NIC is premature because the issue is intermittent and the link light behavior suggests a physical-layer problem, not a hardware failure. The technician should first rule out environmental factors like EMI before replacing components.
★ When this WOULD be the correct answer
This would be correct if the technician had already verified no EMI, replaced the cable and switch port, and the NIC's link light remains off or the device fails to connect at all, indicating a faulty NIC.
Why candidates choose this
Candidates may assume that since the cable and switch port were replaced, the NIC must be the culprit, overlooking that intermittent connectivity often stems from external interference rather than hardware failure.
✗Configure the NIC to use a static IP addressWrong answer — click to see why▾
Why this is wrong here
Configuring a static IP address addresses IP configuration issues, not physical link-layer problems like intermittent link light loss. The symptom (link light turning off) indicates a physical or electrical issue, not a network layer misconfiguration.
★ When this WOULD be the correct answer
A user reports intermittent connectivity but the link light remains on. The technician finds the IP address is obtained via DHCP and suspects a DHCP server issue or IP address conflict. In that scenario, configuring a static IP would be a valid next step to rule out DHCP problems.
Why candidates choose this
Candidates may confuse intermittent connectivity with IP address assignment issues, thinking that a dynamic IP might be causing the drops, especially if they've seen DHCP lease renewal cause brief outages in other contexts.
Analysis generated from the official 220-1101blueprint 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
OSI Model Reference
| Layer | Name | PDU | Key Protocols / Devices |
|---|---|---|---|
| 7 | Application | Data | HTTP, HTTPS, DNS, SMTP, FTP, SSH |
| 6 | Presentation | Data | TLS / SSL, JPEG, ASCII encoding |
| 5 | Session | Data | NetBIOS, RPC, SIP |
| 4 | Transport | Segment / Datagram | TCP, UDP |
| 3 | Network | Packet | IP, ICMP, OSPF — Routers |
| 2 | Data Link | Frame | Ethernet, Wi-Fi, PPP — Switches, Bridges |
| 1 | Physical | Bits | Cables, NICs, Hubs, Repeaters |
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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.