220-1102 Question 182
Single answerWiredA technician is troubleshooting a Windows 11 desktop in an office that uses only wired Ethernet connections. The user reports that the PC suddenly cannot access internal file shares or the internet. The link light on the NIC is off, and Windows shows the network cable as unplugged. The switch port for that desk is known to be working because another laptop connects successfully using the same wall jack and patch cable. Which of the following is the BEST next step?
- A
Run ipconfig /renew to request a new IPv4 address from DHCP
- B
Replace or reseat the Ethernet cable between the wall jack and the desktop's NIC
- C
Flush the DNS cache with ipconfig /flushdns
- D
Disable and re-enable the network adapter in Windows
- E
Change the workstation from DHCP to a static IP configuration
Show answer and explanation
Correct answer: B
Explanation
This question tests practical wired network troubleshooting using the OSI model and CompTIA's expectation that technicians start with the simplest and most likely cause. Because another device works on the same wall jack and patch path, the switch port and in-wall run are likely good. The affected desktop shows no link light and reports the cable as unplugged, which are classic signs of a physical-layer issue. Best practice is to check and reseat cabling, verify a good NIC connection, and swap with known-good cables before moving to software troubleshooting such as DHCP renewal, DNS cache clearing, or adapter resets. This approach is consistent with standard desktop support procedures and Microsoft/enterprise troubleshooting guidance: verify physical connection first, then validate NIC status, then move to TCP/IP settings and higher-layer services.
- A. Incorrect.
Incorrect. Renewing a DHCP lease is useful when the system has a physical link and is failing to obtain or refresh an IP address. In this scenario, Windows reports that the cable is unplugged and the NIC link light is off, which indicates a Layer 1 physical connectivity issue. DHCP cannot function until the physical connection is restored.
- B. Correct.
Correct. The evidence points to a physical wired connectivity problem local to the desktop or its immediate patch connection. The wall jack, switch port, and known-good patch path have effectively been tested by connecting another laptop successfully. The best next step is to reseat or replace the Ethernet cable from the wall jack to the desktop NIC, since that is the remaining simple physical component in the affected system's path and aligns with standard troubleshooting from the physical layer upward.
- C. Incorrect.
Incorrect. Flushing DNS helps when name resolution is the problem, such as when users can reach resources by IP address but not by hostname. Here, the system has no detected physical Ethernet connection, so DNS is not the root cause.
- D. Incorrect.
Incorrect. Disabling and re-enabling the adapter can help with a driver or software state issue, but it is not the best next step when the NIC link light is off and the OS reports the cable as unplugged. Those symptoms strongly indicate a physical connection problem rather than a logical or driver issue.
- E. Incorrect.
Incorrect. Assigning a static IP address does not resolve a missing physical link. Without Layer 1 connectivity, the workstation still would not communicate on the wired network. This option reflects a common misconception that all connectivity problems are IP configuration problems.