CCNP Network Assurance Practice Question
A network engineer is troubleshooting a connectivity problem between two hosts on the same VLAN. The engineer suspects a duplex mismatch on the switch port. Which command should be used to verify the duplex settings on a Cisco Catalyst switch interface?
⚠ Common exam trap
The trap here is assuming that summary commands like show interfaces status provide enough detail to diagnose duplex mismatches, when they actually lack the granular error counters needed.
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
✓
show interfaces gigabitEthernet 0/1
To verify duplex settings on a Cisco Catalyst switch interface, the show interfaces command with the specific interface is the most appropriate because it displays the operational duplex, speed, and error counters. This allows the engineer to quickly identify a duplex mismatch, which often results in late collisions and performance degradation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
show controllers ethernet-controller
Why it's wrong here
The show controllers ethernet-controller command displays low-level hardware statistics and register information, which can be useful for advanced troubleshooting but does not directly show the configured duplex mode. It is not the primary command for verifying duplex settings.
- ✓
show interfaces gigabitEthernet 0/1
Why this is correct
The show interfaces gigabitEthernet 0/1 command provides detailed information about the interface, including duplex, speed, and error counters. This allows the engineer to confirm the operational duplex mode and detect a mismatch. It is the most direct way to verify duplex settings on a specific interface.
- ✗
show interfaces counters errors
Why it's wrong here
The show interfaces counters errors command displays error counters such as FCS, alignment, and runts, which can indicate a duplex mismatch. However, it does not directly show the configured duplex mode. To verify duplex settings, you need to see the operational duplex, not just error statistics.
- ✗
show interfaces status
Why it's wrong here
The show interfaces status command displays summary information such as port status, VLAN, duplex, speed, and type. While it does show duplex, it is a summary and may not provide the detailed error counters needed to confirm a duplex mismatch. For a thorough investigation, a more detailed command is preferred.
Visual reference
About these practice questions
One of 1,923 original 350-401 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
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 Cisco exam blueprint
This 350-401 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 350-401 exam.