220-1101 Hardware and Network Troubleshooting Practice Question
A technician is troubleshooting a workstation that cannot access any network resources. The technician runs ipconfig and sees that the IP address is 169.254.10.50 with subnet mask 255.255.0.0. The link lights on the NIC and the switch port are solid green. The technician connects the workstation to a different wall jack using a known-good cable, but the problem persists. Which of the following is the MOST likely cause?
⚠ Common exam trap
The trap here is that candidates see solid link lights and assume Layer 1 is fine, then jump to a Layer 3 issue like a misconfigured default gateway or DNS, overlooking that APIPA specifically indicates DHCP failure, not routing or name resolution problems.
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
✓
The DHCP server is unavailable
The IP address 169.254.10.50 with subnet mask 255.255.0.0 is an Automatic Private IP Addressing (APIPA) address, assigned by Windows when a DHCP server cannot be reached. Since the link lights are solid green and the cable and wall jack have been swapped with a known-good cable, the issue is not physical layer connectivity. The most likely cause is that the DHCP server is unavailable, preventing the workstation from obtaining a valid IP address.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The switch port is administratively disabled
Why it's wrong here
An administratively disabled switch port is placed into a shutdown state by a network administrator, which typically removes the link at Layer 1. In this state, the switch does not transmit or receive frames, and the link light either remains off or shows an amber/red indicator. Since the scenario states the link light is solid green, the port is administratively up and passing physical-layer signaling; therefore, an administratively disabled port cannot be the reason the workstation lacks network connectivity.
- ✓
The DHCP server is unavailable
Why this is correct
APIPA is automatically assigned Windows when no DHCP response is received. The physical connectivity is good (link lights, cable test), so the failure lies in the DHCP process itself, likely because the DHCP server is down, unreachable, or misconfigured.
- ✗
The default gateway is misconfigured on the router
Why it's wrong here
A misconfigured default gateway on the router would only affect traffic that must leave the local subnet. The workstation’s IP configuration process is completely independent of the router’s gateway setting—DHCP uses Layer 2 broadcast frames within the local segment and does not require a gateway to function. The presence of an APIPA address (169.254.x.x) proves that the workstation never received a DHCP offer, so the DHCP transaction failed before the gateway's configuration could even be considered.
- ✗
The DNS server is not responding
Why it's wrong here
A non-responsive DNS server only prevents name resolution; it does not affect the DHCP process that assigns IP addresses. The workstation can still obtain a valid DHCP lease even if DNS is down, and it would have a routable IP address rather than an APIPA address. Because the symptom is no network access at all—with the APIPA address indicating no DHCP response—the root cause lies in IP address assignment, not in DNS resolution.
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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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.