Quick Answer
The answer is show interfaces, show interfaces terse, and monitor interface. These three operational commands are the primary tools in Junos for monitoring interface statistics and status because they each serve a distinct purpose: show interfaces provides detailed packet counts, errors, and operational state for in-depth analysis; show interfaces terse offers a concise, one-line-per-interface summary of administrative and protocol status for rapid health checks; and monitor interface delivers real-time, continuously updating statistics for live traffic observation. On the JNCIA-Junos exam, this question tests your ability to differentiate between commands that display static output versus dynamic monitoring, and a common trap is confusing the static show interfaces extensive with the real-time monitor interface. To remember, think of the three levels of interface inspection: terse for a quick glance, show for a deep dive, and monitor for live action.
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.
Which THREE operational commands are used to monitor interface statistics and status? (Select three.)
show interfaces terse
Shows a concise status of all interfaces.
monitor interface
Provides real-time interface status and statistics.
show interfaces
Displays interface statistics and detailed info.
show log interfaces
Why wrong: Not a valid command.
show interfaces diagnostics
Why wrong: Shows diagnostics like optical power, not statistics.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
show interfaces terse
Option A is correct because 'show interfaces terse' provides a concise summary of all interfaces, including their administrative and operational status (up/down) and protocol states, making it ideal for a quick health check. Option B is correct because 'monitor interface' is a real-time operational command that continuously displays interface statistics and status updates, useful for live traffic observation. Option C is correct because 'show interfaces' displays detailed interface statistics, including packet counts, errors, and operational status, which is the primary command for in-depth interface monitoring.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
show interfaces terse
Why this is correct
Shows a concise status of all interfaces.
Related concept
Read the scenario before looking for a memorised answer.
monitor interface
Why this is correct
Provides real-time interface status and statistics.
Related concept
Read the scenario before looking for a memorised answer.
show interfaces
Why this is correct
Displays interface statistics and detailed info.
Related concept
Read the scenario before looking for a memorised answer.
show log interfaces
Why it's wrong here
Not a valid command.
show interfaces diagnostics
Why it's wrong here
Shows diagnostics like optical power, not statistics.
Common exam traps
The trap here is that candidates may confuse 'show log interfaces' with the valid 'show log' command or mistakenly think 'show interfaces diagnostics' is a catch-all command, when in reality Junos requires specific sub-commands like 'show interfaces diagnostics optics' for optics monitoring.
Trap categories for this question
Command / output trap
Not a valid command.
Detailed technical explanation
Junos uses a unified 'show interfaces' command family, where adding keywords like 'terse' or 'extensive' modifies the output verbosity. The 'monitor interface' command leverages the Junos event-driven architecture to poll interface counters at a configurable interval (default 1 second), displaying real-time delta values. In production networks, 'show interfaces terse' is often used in scripts to quickly detect link flaps, while 'monitor interface' is invaluable during troubleshooting to spot intermittent errors like CRC errors or packet drops as they occur.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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
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FAQ
Operational Monitoring and Maintenance — This question tests Operational Monitoring and Maintenance — Read the scenario before looking for a memorised answer..
The correct answer is: show interfaces terse — Option A is correct because 'show interfaces terse' provides a concise summary of all interfaces, including their administrative and operational status (up/down) and protocol states, making it ideal for a quick health check. Option B is correct because 'monitor interface' is a real-time operational command that continuously displays interface statistics and status updates, useful for live traffic observation. Option C is correct because 'show interfaces' displays detailed interface statistics, including packet counts, errors, and operational status, which is the primary command for in-depth interface monitoring.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
This JNCIA-JUNOS practice question is part of Courseiva's free Juniper Networks 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 JNCIA-JUNOS exam.
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