CompTIA Network+ (N10-009)Network TroubleshootingEasy
A user reports that their workstation is unable to connect to the network. The technician observes that the link lights on both the workstation's network interface card (NIC) and the switch port are unlit. Which of the following is the MOST appropriate initial step for the technician to take?
- AVerify the workstation's NIC drivers are up to date.
- BCheck the workstation's IP configuration using `ipconfig` or `ifconfig`.
- CReboot the switch the workstation is connected to.
- DReplace the network cable connecting the workstation to the switch.
Show answer & explanationAnswer & explanation
Correct answer: D. Replace the network cable connecting the workstation to the switch.
Unlit link lights on both the NIC and the switch port indicate a problem at the physical layer, specifically that no physical connection is being detected. The most common and easiest issue to check and resolve for this symptom is a faulty or disconnected network cable.
Why the other options are wrong
- A. NIC drivers are related to how the operating system interacts with the NIC, not the physical link establishment itself, especially if the link light is off.
- B. Checking IP configuration is a Layer 3 step; the problem is indicated at Layer 1 (physical).
- C. Rebooting the switch is a more disruptive step and is unlikely to resolve a physical cable issue.
Unlit Link Lights
Indicates a lack of physical connection or active link between two network devices, typically at Layer 1 of the OSI model.
- Symptoms: No network connectivity, no link activity.
- Common causes: Disconnected cable, faulty cable, faulty NIC/port, device powered off.
- Troubleshooting starts with checking physical connections.
Memory trick: No light, no fight! Check the cable, make it right.