The answer is a faulty wall jack termination. When a computer works on one jack but shows no link light on another, the issue is almost always a physical wiring problem at the new location, not the device or switch port. A link light requires a complete electrical circuit through all eight wires of the Ethernet cable; if the wall jack is terminated incorrectly—such as using the wrong wiring standard (T568A vs. T568B) or failing to fully punch down a pair—the circuit breaks, and the switch cannot establish a link. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your understanding of physical layer troubleshooting, specifically that a missing link light points to a Layer 1 fault. A common trap is blaming the patch cable or switch port, but the key clue is that the problem follows the wall jack, not the computer. Remember: no link light means no electrical continuity—check the termination first, not the hardware.
220-1101 Cabling Practice Question
This 220-1201 practice question tests your understanding of cabling. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A user reports that their computer connected to a wall jack works fine, but when they move the computer to a different desk and plug into a different wall jack, there is no network connectivity. The switch port shows no link light. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The wall jack is terminated incorrectly.
This question tests understanding of cable termination and wiring standards. A faulty termination at the wall jack or patch panel is a common cause of intermittent or no connectivity. The correct answer focuses on the physical connection at the new location.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 computer's NIC is faulty.
Why it's wrong here
The NIC worked at the previous desk, so it is unlikely to be the issue.
✗
The patch cable is not a crossover cable.
Why it's wrong here
Modern NICs auto-MDIX, so crossover cables are not needed.
✓
The wall jack is terminated incorrectly.
Why this is correct
An incorrect termination at the new jack would prevent a link, explaining the no-link light.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
The switch port is administratively down.
Why it's wrong here
While possible, it is less likely than a physical termination issue, especially if other ports work.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 220-1201 question in full detail.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 220-1201 NAT questions on configuration and troubleshooting.
Cabling — This question tests Cabling — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The wall jack is terminated incorrectly. — This question tests understanding of cable termination and wiring standards. A faulty termination at the wall jack or patch panel is a common cause of intermittent or no connectivity. The correct answer focuses on the physical connection at the new location.
What should I do if I get this 220-1201 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 220-1201 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This 220-1201 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 220-1201 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.