220-1101 Networking Practice Question
A user in a small office reports that their computer cannot access the internet. The technician runs ipconfig and sees the IP address is 169.254.15.22. The technician checks the network cable and sees link lights on the NIC and the wall jack. Which of the following is the MOST likely cause of this issue?
⚠ Common exam trap
The trap here is that candidates see active link lights and assume the network is fully functional, overlooking that DHCP operates at Layer 3 (Network layer) and can fail even when Layer 1 (Physical) and Layer 2 (Data Link) are working.
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 or is unreachable
The IP address 169.254.15.22 is an Automatic Private IP Addressing (APIPA) address (169.254.0.0/16 range), which Windows assigns when a DHCP server cannot be reached. Since the link lights are active, the physical layer is functional, ruling out a cable fault. The most likely cause is that the DHCP server is not responding or is unreachable, preventing the client 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 network cable is faulty
Why it's wrong here
An active link light on the NIC and switch port indicates the physical layer (cable, connectors, and link negotiation) is functioning correctly. A faulty or disconnected cable would prevent link synchronization, causing no link light and zero network connectivity—rather than a 169.254 APIPA address, which specifically results from DHCP failure over an otherwise working link.
When this WOULD be correct
A user cannot connect to the network, and the technician sees no link lights on the NIC after reseating the cable. In that case, a faulty cable would be a likely cause.
- ✓
The DHCP server is not responding or is unreachable
Why this is correct
When a Windows computer is configured for DHCP and fails to receive a DHCP offer after retrying (typically via broadcast Discover messages), it auto-configures an APIPA address in the 169.254.0.0/16 range. This link-local address is only valid for local subnet communication and prevents internet/network access, making an unreachable or unresponsive DHCP server the most plausible root cause.
- ✗
The user's computer has a duplicate IP address on the network
Why it's wrong here
A duplicate IP address is typically detected via Address Resolution Protocol (ARP) probes; the OS then alerts the user with a conflict message and may temporarily disable the interface, causing intermittent connectivity—not an automatic APIPA assignment. APIPA only occurs when the DHCP client cannot obtain any lease at all, so a duplicate address (which still implies a leased IP) cannot be the cause here.
When this WOULD be correct
A user reports intermittent connectivity and an IP conflict message. The technician finds two devices with the same static IP on the network. In this scenario, duplicate IP is the most likely cause.
- ✗
The subnet mask is incorrectly configured
Why it's wrong here
An incorrect subnet mask on the client would not prevent DHCP from assigning an IP address; the device would still receive a lease and show an address within the DHCP scope. APIPA is triggered solely by the absence of a DHCP response, and subnet mask misconfiguration is a post-lease issue that affects routing and local communication, not the lease acquisition process itself.
When this WOULD be correct
A user cannot access network resources, and ipconfig shows a valid IP address (e.g., 192.168.1.10) but with a subnet mask of 255.255.0.0 instead of 255.255.255.0. This would cause communication failures with devices on different subnets.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 220-1101 exam frequently reuses these exact scenarios with slightly different constraints.
✓The DHCP server is not responding or is unreachableCorrect answer▾
Why this is correct
When a Windows computer is configured for DHCP and fails to receive a DHCP offer after retrying (typically via broadcast Discover messages), it auto-configures an APIPA address in the 169.254.0.0/16 range. This link-local address is only valid for local subnet communication and prevents internet/network access, making an unreachable or unresponsive DHCP server the most plausible root cause.
✗The network cable is faultyWrong answer — click to see why▾
Why this is wrong here
The link lights on both the NIC and the wall jack indicate the physical cable connection is good, so a faulty cable is unlikely to be the cause of the APIPA address.
★ When this WOULD be the correct answer
A user cannot connect to the network, and the technician sees no link lights on the NIC after reseating the cable. In that case, a faulty cable would be a likely cause.
Why candidates choose this
Candidates often assume that any network issue is due to a bad cable, especially when the problem is intermittent or after physical disturbance, without checking link lights first.
✗The user's computer has a duplicate IP address on the networkWrong answer — click to see why▾
Why this is wrong here
A duplicate IP address would cause an IP conflict error, not an APIPA address (169.254.x.x). The computer would still have a valid IP from DHCP or static configuration, not a self-assigned one.
★ When this WOULD be the correct answer
A user reports intermittent connectivity and an IP conflict message. The technician finds two devices with the same static IP on the network. In this scenario, duplicate IP is the most likely cause.
Why candidates choose this
Candidates may confuse symptoms of duplicate IP (conflict messages, connectivity issues) with APIPA, not realizing that APIPA specifically indicates DHCP failure, not IP duplication.
✗The subnet mask is incorrectly configuredWrong answer — click to see why▾
Why this is wrong here
An incorrectly configured subnet mask would not cause the computer to obtain an APIPA address (169.254.x.x). APIPA addresses are assigned automatically when DHCP fails, not due to subnet mask misconfiguration.
★ When this WOULD be the correct answer
A user cannot access network resources, and ipconfig shows a valid IP address (e.g., 192.168.1.10) but with a subnet mask of 255.255.0.0 instead of 255.255.255.0. This would cause communication failures with devices on different subnets.
Why candidates choose this
Candidates may confuse subnet mask issues with DHCP failures because both can cause connectivity problems, and they might think an incorrect subnet mask could lead to an APIPA address.
Analysis generated from the official 220-1101blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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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JA
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.