220-1101 Networking Practice Question
A small office has 10 computers connected to a single switch. The ISP provides a modem with a built-in router and DHCP server. One user reports they cannot access the internet but can access shared files on the local network. The technician checks the IP configuration on the user's computer and sees an IP address of 169.254.12.5. Which of the following is the MOST likely cause?
⚠ Common exam trap
Many exam-takers confuse APIPA with a DNS or gateway issue, but the 169.254.x.x address is a definitive indicator of DHCP failure, not a misconfiguration of higher-layer services.
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 169.254.12.5 is an Automatic Private IP Addressing (APIPA) address (169.254.0.0/16 range), which Windows assigns when a DHCP discovery request fails to receive a response. Since the user can access local network shares but not the internet, the DHCP server (built into the ISP modem/router) is unavailable or unreachable, preventing the computer from obtaining a valid IP configuration.
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 down
Why it's wrong here
A DNS server outage would prevent the resolution of hostnames to IP addresses, so you could not connect to resources by name (e.g., a web URL). However, the client would still have successfully obtained a valid routable IP address from DHCP, and that address would appear in ipconfig—not an APIPA 169.254.x.x address. The presence of an APIPA address specifically points to a failure in IP address allocation, not name resolution, so a DNS failure is not the cause of this symptom.
- ✓
The DHCP server is unavailable
Why this is correct
When a Windows client cannot reach a DHCP server, it automatically falls back to Automatic Private IP Addressing (APIPA) and assigns itself an address in the 169.254.0.0/16 range. Since the user still has local file access, the switch is forwarding frames, but the DHCP server—likely a router or separate server that is down or unreachable—never responded to the DHCPDISCOVER message. This explains both the lack of a routable IP and the inability to reach the internet, making the unavailable DHCP server the correct root cause.
- ✗
The default gateway is misconfigured
Why it's wrong here
A misconfigured default gateway would still leave the client with a valid, DHCP-assigned IP address, such as a 192.168.1.10 or 10.0.0.50. That address would appear in the TCP/IP configuration, and only traffic destined for other subnets or the internet would fail; local network communication would remain intact. The APIPA address 169.254.x.x is a strong indicator that DHCP itself never provided a lease, so a gateway misconfiguration would not produce this addressing symptom.
- ✗
The switch port is faulty
Why it's wrong here
If the switch port were faulty—whether due to a bad cable, port electronics, or configuration—the client would experience a complete loss of link-layer connectivity. That would prevent not only internet access but also all local communications, including the file sharing that the user still has, because the NIC would not receive a link signal or would drop all frames. Since the computer remains able to reach other local devices, the switch port is functionally operational; the APIPA address is a separate DHCP-allocation failure, not a Layer 1/2 issue.
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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.