- A
1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Use 'show interfaces' to check for CRC errors and duplex mismatch 4. Enter global configuration mode 5. Use 'interface' command to enter the specific interface 6. Use 'duplex full' to set duplex manually 7. Use 'speed 100' to set speed manually 8. Use 'end' to exit configuration mode 9. Use 'copy running-config startup-config' to save
Why wrong: This is the correct sequence: first access the device, then gather diagnostic information with 'show interfaces', then enter configuration mode to apply the fix (set duplex and speed manually), and finally save the configuration.
- B
1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Enter global configuration mode 4. Use 'interface' command to enter the specific interface 5. Use 'duplex full' to set duplex manually 6. Use 'speed 100' to set speed manually 7. Use 'end' to exit configuration mode 8. Use 'show interfaces' to check for CRC errors and duplex mismatch 9. Use 'copy running-config startup-config' to save
This is incorrect because it applies the fix before gathering diagnostic information. The correct sequence requires checking the interface status first to confirm the issue.
- C
1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Use 'show interfaces' to check for CRC errors and duplex mismatch 4. Enter global configuration mode 5. Use 'interface' command to enter the specific interface 6. Use 'speed 100' to set speed manually 7. Use 'duplex full' to set duplex manually 8. Use 'end' to exit configuration mode 9. Use 'copy running-config startup-config' to save
This sequence correctly diagnoses the issue with 'show interfaces' before making changes, and applies speed before duplex to prevent the duplex from being automatically reset, which is the standard safe practice.
- D
1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Use 'show interfaces' to check for CRC errors and duplex mismatch 4. Enter global configuration mode 5. Use 'interface' command to enter the specific interface 6. Use 'duplex full' to set duplex manually 7. Use 'speed 100' to set speed manually 8. Use 'copy running-config startup-config' to save 9. Use 'end' to exit configuration mode
This is incorrect because saving the configuration should be the last step after exiting configuration mode. Exiting with 'end' before saving ensures the running config is complete.
Quick Answer
The correct order for duplex mismatch troubleshooting steps on Cisco IOS-XE is: connect via console or SSH, enter privileged EXEC mode, run show interfaces to check for CRC errors and duplex mismatch, enter global configuration mode, use the interface command to select the specific port, set speed 100 first, then duplex full, exit with end, and finally save with copy running-config startup-config. This sequence is critical because setting speed before duplex prevents the interface from reverting to auto-negotiation defaults, which would undo the manual duplex setting and leave the mismatch unresolved. On the CCNA 200-301 v2 exam, this drag-and-drop task tests your understanding of interface troubleshooting logic and the IOS-XE CLI hierarchy; a common trap is placing duplex before speed or forgetting to save the config. Remember the mnemonic “Speed before Duplex, Save before Exit” to lock in the correct order and avoid losing points on the exam.
CCNA Network Infrastructure and Connectivity Practice Question
This 200-301 practice question tests your understanding of network infrastructure and connectivity. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Drag and drop the following steps into the correct order to troubleshoot a suspected duplex mismatch and CRC errors on an interface using Cisco IOS-XE CLI commands.
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
1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Enter global configuration mode 4. Use 'interface' command to enter the specific interface 5. Use 'duplex full' to set duplex manually 6. Use 'speed 100' to set speed manually 7. Use 'end' to exit configuration mode 8. Use 'show interfaces' to check for CRC errors and duplex mismatch 9. Use 'copy running-config startup-config' to save
First, access the device and enter privileged mode, then run 'show interfaces' to diagnose CRC errors and confirm a duplex mismatch. Next, enter configuration mode and set the speed manually before duplex; setting speed first prevents the duplex from reverting to auto. Finally, exit configuration mode and save the running config to ensure the change persists.
Key principle: Authentication proves identity; authorization controls what that identity can do after login. Both must work for full privileged access.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Use 'show interfaces' to check for CRC errors and duplex mismatch 4. Enter global configuration mode 5. Use 'interface' command to enter the specific interface 6. Use 'duplex full' to set duplex manually 7. Use 'speed 100' to set speed manually 8. Use 'end' to exit configuration mode 9. Use 'copy running-config startup-config' to save
Why it's wrong here
This is the correct sequence: first access the device, then gather diagnostic information with 'show interfaces', then enter configuration mode to apply the fix (set duplex and speed manually), and finally save the configuration.
When this WOULD be correct
This sequence is used when troubleshooting duplex mismatch and CRC errors on a Cisco IOS-XE device, ensuring systematic problem isolation and resolution.
- ✓
1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Enter global configuration mode 4. Use 'interface' command to enter the specific interface 5. Use 'duplex full' to set duplex manually 6. Use 'speed 100' to set speed manually 7. Use 'end' to exit configuration mode 8. Use 'show interfaces' to check for CRC errors and duplex mismatch 9. Use 'copy running-config startup-config' to save
Why this is correct
This is incorrect because it applies the fix before gathering diagnostic information. The correct sequence requires checking the interface status first to confirm the issue.
Related concept
Authentication checks who the user is.
- ✓
1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Use 'show interfaces' to check for CRC errors and duplex mismatch 4. Enter global configuration mode 5. Use 'interface' command to enter the specific interface 6. Use 'speed 100' to set speed manually 7. Use 'duplex full' to set duplex manually 8. Use 'end' to exit configuration mode 9. Use 'copy running-config startup-config' to save
Why this is correct
This sequence correctly diagnoses the issue with 'show interfaces' before making changes, and applies speed before duplex to prevent the duplex from being automatically reset, which is the standard safe practice.
Related concept
Authentication checks who the user is.
- ✓
1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Use 'show interfaces' to check for CRC errors and duplex mismatch 4. Enter global configuration mode 5. Use 'interface' command to enter the specific interface 6. Use 'duplex full' to set duplex manually 7. Use 'speed 100' to set speed manually 8. Use 'copy running-config startup-config' to save 9. Use 'end' to exit configuration mode
Why this is correct
This is incorrect because saving the configuration should be the last step after exiting configuration mode. Exiting with 'end' before saving ensures the running config is complete.
Related concept
Authentication checks who the user is.
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.
✓1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Enter global configuration mode 4. Use 'interface' command to enter the specific interface 5. Use 'duplex full' to set duplex manually 6. Use 'speed 100' to set speed manually 7. Use 'end' to exit configuration mode 8. Use 'show interfaces' to check for CRC errors and duplex mismatch 9. Use 'copy running-config startup-config' to saveCorrect answer▾
Why this is correct
This is incorrect because it applies the fix before gathering diagnostic information. The correct sequence requires checking the interface status first to confirm the issue.
✗1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Use 'show interfaces' to check for CRC errors and duplex mismatch 4. Enter global configuration mode 5. Use 'interface' command to enter the specific interface 6. Use 'duplex full' to set duplex manually 7. Use 'speed 100' to set speed manually 8. Use 'end' to exit configuration mode 9. Use 'copy running-config startup-config' to saveWrong answer — click to see why▾
Why this is wrong here
Configuring duplex before speed can cause the duplex to revert to auto, failing to permanently fix the mismatch.
★ When this WOULD be the correct answer
This sequence is used when troubleshooting duplex mismatch and CRC errors on a Cisco IOS-XE device, ensuring systematic problem isolation and resolution.
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?”
Common exam traps
Common exam trap: authentication is not authorization
Logging in proves the user can authenticate. It does not automatically mean the user is allowed to enter privileged or configuration mode. Watch for AAA authorization, privilege level and command authorization details.
Trap categories for this question
Command / output trap
This is the correct sequence: first access the device, then gather diagnostic information with 'show interfaces', then enter configuration mode to apply the fix (set duplex and speed manually), and finally save the configuration.
Detailed technical explanation
How to think about this question
This kind of question is testing the difference between identity and permission. A user may successfully log in to a router because authentication is working, but still fail to enter configuration mode because authorization is missing, misconfigured or mapped to a lower privilege level.
KKey Concepts to Remember
- Authentication checks who the user is.
- Authorization controls what the user is allowed to do after login.
- Privilege levels affect access to EXEC and configuration commands.
- AAA, TACACS+ and RADIUS can separate login success from command access.
TExam Day Tips
- Do not assume successful login means full administrative access.
- Look for words such as cannot enter configuration mode, privilege level, authorization or command access.
- Separate login problems from permission problems before choosing the answer.
Key takeaway
Authentication proves identity; authorization controls what that identity can do after login. Both must work for full privileged access.
Real-world example
How this comes up in practice
A junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.
What to study next
Got this wrong? Here's your next step.
Review Cisco AAA concepts — authentication, authorization, and accounting. Study privilege levels (0–15), command authorization under TACACS+, and how RADIUS differs. Then practise related 200-301 questions on access control and AAA configuration.
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Network Infrastructure and Connectivity — study guide chapter
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FAQ
Questions learners often ask
What does this 200-301 question test?
Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — Authentication checks who the user is..
What is the correct answer to this question?
The correct answer is: 1. Connect to the device via console or SSH 2. Enter privileged EXEC mode 3. Enter global configuration mode 4. Use 'interface' command to enter the specific interface 5. Use 'duplex full' to set duplex manually 6. Use 'speed 100' to set speed manually 7. Use 'end' to exit configuration mode 8. Use 'show interfaces' to check for CRC errors and duplex mismatch 9. Use 'copy running-config startup-config' to save — First, access the device and enter privileged mode, then run 'show interfaces' to diagnose CRC errors and confirm a duplex mismatch. Next, enter configuration mode and set the speed manually before duplex; setting speed first prevents the duplex from reverting to auto. Finally, exit configuration mode and save the running config to ensure the change persists.
What should I do if I get this 200-301 question wrong?
Review Cisco AAA concepts — authentication, authorization, and accounting. Study privilege levels (0–15), command authorization under TACACS+, and how RADIUS differs. Then practise related 200-301 questions on access control and AAA configuration.
What is the key concept behind this question?
Authentication checks who the user is.
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 →
Same concept, more angles
3 more ways this is tested on 200-301
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Drag and drop the following steps into the correct order to troubleshoot a suspected duplex mismatch and CRC errors on a Cisco switch interface.
medium- ✓ A.Enter privileged EXEC mode using the 'enable' command.
- ✓ B.Use the 'show interfaces' command to check for CRC errors and duplex mismatch.
- ✓ C.Configure the interface with the 'duplex full' command to fix the mismatch.
- ✓ D.Enter global configuration mode using the 'configure terminal' command.
Why A: Troubleshooting starts from privileged EXEC, checking errors, identifying the problematic interface, then configuring the correct duplex setting.
Variation 2. Drag and drop the following steps into the correct order to troubleshoot and resolve excessive interface errors caused by a duplex mismatch on a Cisco switch interface.
medium- ✓ A.Use the show interfaces command to examine the input errors, CRC, and late collisions counters.
- ✓ B.Use the show interfaces status command to display the current speed and duplex settings for the interface.
- ✓ C.View the connected device's speed and duplex configuration using the show cdp neighbors detail command.
- ✓ D.Configure the interface with the matching or auto-negotiated speed and duplex settings using the speed and duplex commands.
- ✓ E.Issue the show interfaces command again to confirm that the error counters have stopped increasing and the interface is operating normally.
Why A: The correct order starts with identifying symptoms using show interfaces to see error counters like CRC and late collisions. Next, check the local interface speed and duplex with show interfaces status. Then discover the neighbor's speed and duplex, for instance via show cdp neighbors detail, to confirm a mismatch. After identifying the mismatch, configure the interface with the correct settings (e.g., speed and duplex commands). Finally, verify the resolution by running show interfaces again to ensure errors are no longer incrementing.
Variation 3. Drag and drop the following steps into the correct order to troubleshoot a suspected duplex mismatch and CRC errors on a Cisco switch interface using CLI commands.
medium- ✓ A.1. Use 'show interfaces' to check for CRC errors and duplex mismatch. 2. Manually set speed and duplex on both ends to match. 3. Use 'clear counters' to reset interface statistics. 4. Use 'show interfaces' again to verify no new errors.
- B.1. Use 'clear counters' to reset interface statistics. 2. Use 'show interfaces' to check for CRC errors. 3. Manually set speed and duplex on both ends to match. 4. Use 'show interfaces' again to verify no new errors.
- C.1. Use 'show interfaces' to check for CRC errors. 2. Use 'clear counters' to reset interface statistics. 3. Manually set speed and duplex on both ends to match. 4. Use 'show interfaces' again to verify no new errors.
- D.1. Manually set speed and duplex on both ends to match. 2. Use 'show interfaces' to check for CRC errors. 3. Use 'clear counters' to reset interface statistics. 4. Use 'show interfaces' again to verify no new errors.
Why A: Start by examining current interface stats, then fix the mismatch, and finally clear and recheck counters.
Last reviewed: Jun 6, 2026
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