The answer is the 'show interfaces errors' and 'show interfaces extensive' commands. These two commands provide the error counter information needed to check interface packet errors because 'show interfaces errors' delivers a concise, per-interface summary of all error counters, while 'show interfaces extensive' includes the same detailed error statistics alongside other operational data. On the JNCIA-Junos exam, this tests your ability to recall which operational commands surface error data versus those that omit it; a common trap is confusing 'show interfaces terse' (which shows only a brief summary without errors) or using the invalid singular 'show interface' syntax. To remember, think of the word "errors" as your direct keyword—if the command name includes "errors" or "extensive," you’ll find the packet error counters you need.
JNCIA-JUNOS Operational Monitoring and Maintenance Practice Question
This JNCIA-JUNOS practice question tests your understanding of operational monitoring and maintenance. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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.
An engineer needs to check for packet errors on an interface. Which two commands provide error counter information? (Choose two.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
show interfaces extensive
Option B, 'show interfaces errors', provides a concise view of error counters per interface. Option C, 'show interfaces extensive', includes detailed error statistics. Option A shows a brief summary without errors. Option D is invalid syntax (singular 'interface'). Option E shows optical diagnostics, not packet errors.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 interfaces diagnostics
Why it's wrong here
'show interfaces diagnostics' shows optical and physical diagnostics, not packet errors.
✗
show interface errors
Why it's wrong here
The correct command is 'show interfaces errors' (plural 'interfaces'). This singular form is invalid.
✓
show interfaces extensive
Why this is correct
'show interfaces extensive' includes detailed error counters among other information.
Related concept
Read the scenario before looking for a memorised answer.
✓
show interfaces errors
Why this is correct
'show interfaces errors' displays error statistics for each interface.
Related concept
Read the scenario before looking for a memorised answer.
✗
show interfaces terse
Why it's wrong here
'show interfaces terse' shows a brief status summary, not error counters.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Trap categories for this question
Command / output trap
'show interfaces diagnostics' shows optical and physical diagnostics, not packet errors.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the JNCIA-JUNOS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which JNCIA-JUNOS exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Operational Monitoring and Maintenance — This question tests Operational Monitoring and Maintenance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: show interfaces extensive — Option B, 'show interfaces errors', provides a concise view of error counters per interface. Option C, 'show interfaces extensive', includes detailed error statistics. Option A shows a brief summary without errors. Option D is invalid syntax (singular 'interface'). Option E shows optical diagnostics, not packet errors.
What should I do if I get this JNCIA-JUNOS question wrong?
Identify which JNCIA-JUNOS exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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