CCNA Network Infrastructure and Connectivity Practice Question
A network administrator is troubleshooting a user's wired workstation that cannot access the internet. The user reports that the workstation was working earlier today. The administrator runs 'ipconfig /all' on the workstation and sees an IP address of 169.254.10.55. What is the most likely cause of this issue?
⚠ Common exam trap
Cisco often tests the concept that APIPA addresses are only generated when the DHCP client cannot communicate with any DHCP server, not when there is a configuration mismatch or server-side issue that still allows Layer 2 connectivity.
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 workstation is unable to communicate with a DHCP server due to a faulty network cable.
The IP address 169.254.10.55 falls within the Automatic Private IP Addressing (APIPA) range (169.254.0.0/16, RFC 3927). This address is assigned by the operating system when a DHCP client fails to receive a response from a DHCP server. A faulty network cable would prevent the workstation from communicating with the DHCP server, causing the client to self-assign an APIPA address after the DHCP discovery process times out.
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 workstation has a duplicate IP address conflict with another device.
Why it's wrong here
A duplicate IP address conflict occurs when two devices on the same subnet are configured with the same static IP or when DHCP grants an address already in use. When Windows detects a conflict, it typically displays an error and suppresses the network interface for that address, but it does not automatically fall back to APIPA. In fact, the workstation would retain the conflicting IP address (or stop using it entirely), not transition to a 169.254.x.x address. An APIPA address is self-assigned by the client only when DHCP discovery fails, so a duplicate IP would not cause that fallback behavior.
- ✓
The workstation is unable to communicate with a DHCP server due to a faulty network cable.
Why this is correct
A faulty network cable prevents the workstation from establishing physical layer connectivity, which means it cannot send or receive any frames, including DHCP discover messages. Without receiving a DHCP offer, the workstation's DHCP client times out and automatically assigns itself an APIPA address from the 169.254.0.0/16 range. This is the classic symptom of a DHCP server being unreachable due to a Layer 1 issue: the client has no IP configuration and falls back to link-local addressing. The workstation will also show a network cable unplugged or limited connectivity notification, confirming the physical fault rather than a logical misconfiguration.
- ✗
The workstation's DNS server settings are misconfigured.
Why it's wrong here
DNS server settings are irrelevant to the DHCP address assignment process. A misconfigured DNS server would still allow the workstation to obtain a valid IP address from DHCP; only name resolution would fail afterward. APIPA addresses are assigned by the client itself when DHCP is unavailable, before any DNS queries are made. Since DNS misconfiguration does not prevent DHCP communication, it would never result in a 169.254.x.x address being assigned.
- ✗
The workstation is connected to the wrong VLAN, causing it to receive an incorrect IP address.
Why it's wrong here
Connecting the workstation to the wrong VLAN would typically place it in a different Layer 2 broadcast domain with a distinct IP subnet. DHCP discovery messages are broadcasts, so if the DHCP server for that VLAN is reachable and has a valid scope, the workstation would receive a normal IP address from that scope—not an APIPA address. An APIPA address (169.254.x.x) is only assigned when no DHCP server responds at all, which is not the direct effect of a VLAN mismatch. If the server were unreachable because of the VLAN mismatch, the outcome would be similar to a DHCP failure, but the root cause would be a routing or VLAN configuration issue, not the workstation receiving an incorrect IP address.
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 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓The workstation is unable to communicate with a DHCP server due to a faulty network cable.Correct answer▾
Why this is correct
A faulty network cable prevents the workstation from establishing physical layer connectivity, which means it cannot send or receive any frames, including DHCP discover messages. Without receiving a DHCP offer, the workstation's DHCP client times out and automatically assigns itself an APIPA address from the 169.254.0.0/16 range. This is the classic symptom of a DHCP server being unreachable due to a Layer 1 issue: the client has no IP configuration and falls back to link-local addressing. The workstation will also show a network cable unplugged or limited connectivity notification, confirming the physical fault rather than a logical misconfiguration.
✗The workstation has a duplicate IP address conflict with another device.Wrong answer — click to see why▾
Why this is wrong here
A duplicate IP address conflict would generate an error message and the workstation would still attempt to use the conflicting IP, not fall back to APIPA. The workstation would retain its DHCP-assigned address and display a conflict notification.
Why candidates choose this
Students may confuse the symptoms of a duplicate IP conflict with APIPA, as both can cause connectivity issues. However, APIPA addresses are self-assigned only when DHCP fails, not due to conflicts.
✗The workstation's DNS server settings are misconfigured.Wrong answer — click to see why▾
Why this is wrong here
DNS misconfiguration would affect name resolution, but the workstation would still obtain a valid IP address from DHCP, not an APIPA address. APIPA is only triggered when DHCP discovery fails entirely.
Why candidates choose this
Students often associate DNS with internet access problems, but APIPA addresses indicate a lack of DHCP communication, not DNS issues. The 169.254.x.x range is a clear indicator of DHCP failure.
✗The workstation is connected to the wrong VLAN, causing it to receive an incorrect IP address.Wrong answer — click to see why▾
Why this is wrong here
Being on the wrong VLAN would likely result in an IP from a different subnet, not an APIPA address, unless the DHCP server for that VLAN is unreachable. APIPA occurs only when no DHCP server is reachable at all.
Why candidates choose this
VLAN misconfiguration can cause connectivity issues, but it typically results in a valid IP from the wrong subnet rather than a link-local address. Students may overlook that APIPA is specific to DHCP failure.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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Related to this question
Learn chapter
IPv4 Addressing and Address Classes
Key term
Automatic Private Internet Protocol Addressing
A fallback method used by a device to automatically assign itself an IP address when it cannot obtain one from a DHCP server.
Key term
DHCP server
A DHCP server is a network device or service that automatically assigns IP addresses and other network configuration parameters to devices on a network, eliminating the need for manual configuration.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco 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 200-301 exam.