FC0-U71 Infrastructure Practice Question
A technician is troubleshooting a workstation that randomly loses its connection to a file server. The workstation's IP address is 169.254.10.25, and it cannot reach the default gateway. The switch port shows link and activity lights. Which of the following is the MOST likely cause?
⚠ Common exam trap
The trap here is focusing on the file server or DNS when the link-local address already proves the workstation never received a valid IP configuration.
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 not responding to requests.
An address in the 169.254.0.0/16 range is self-assigned by the operating system when DHCP attempts fail. Because no lease is obtained, no default gateway or DNS servers are provided either, which explains why the workstation cannot reach the file server. Link lights confirm the cable and switch port are working, so the next step is to investigate the DHCP server, scope, or relay.
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 DNS server is unreachable.
Why it's wrong here
An unreachable DNS server would prevent name resolution, so the user could not reach the server by hostname, but it would not produce a 169.254 address. The workstation would still have a valid DHCP-assigned IP and could reach the gateway by IP address. Since the address itself is in the link-local range, the problem occurs before DNS is consulted, making this option inconsistent with the symptom.
- ✓
The DHCP server is not responding to requests.
Why this is correct
When a DHCP client cannot obtain a lease, Windows and many other operating systems self-assign an address in the 169.254.0.0/16 range, known as APIPA or link-local. That address has no gateway, so the workstation cannot reach the file server on another subnet. The link lights confirm the physical connection is fine, which points to a DHCP communication failure rather than a cable or switch port problem.
- ✗
The network cable is damaged or disconnected.
Why it's wrong here
A damaged or disconnected cable would usually result in no link light on the switch port or the workstation. The scenario states the switch port shows link and activity, which indicates the physical layer is functioning. While a marginal cable could cause intermittent drops, it would not consistently produce a link-local address while maintaining link. The APIPA address is a stronger clue pointing to DHCP.
- ✗
The file server's firewall is blocking SMB traffic.
Why it's wrong here
A firewall blocking SMB would prevent file share access even with a valid IP configuration, but it would not cause the workstation to self-assign a 169.254 address. The workstation would still have its DHCP lease and could ping the gateway. Since the address is link-local, the failure occurs at IP configuration, before any SMB session is attempted, so this option does not fit the evidence.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This FC0-U71 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 FC0-U71 exam.