Quick Answer
The answer is to use the 'commit confirmed' command. This is the correct choice because it allows an administrator to apply configuration changes with a built-in safety net: if the changes cause a loss of connectivity, the device automatically reverts to the previous configuration once the confirmation timeout expires, defaulting to ten minutes. On the Juniper Networks Certified Associate Junos JNCIA-Junos exam, this concept tests your understanding of operational safety and rollback mechanisms, often appearing in scenarios where you must prevent a commit confirmed revert connectivity loss situation from locking you out. A common trap is confusing this with a standard commit or a rollback command—remember, only 'commit confirmed' provides an automatic fallback if connectivity drops. For a quick memory tip, think of it as a "safety timer": confirm the commit before the timer runs out, or Junos reverts your changes automatically.
This JNCIA-JUNOS practice question tests your understanding of junos configuration basics. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 administrator makes changes to the candidate configuration and wants to automatically revert to the previous configuration if the changes cause a loss of connectivity. Which method should be used?
Use the 'commit check' command.
Why wrong: This only validates syntax, not connectivity.
Use the 'commit synchronize' command.
Why wrong: Used for dual Routing Engines, not for automatic rollback.
Use the 'rollback' command.
Why wrong: Manual rollback, not automatic.
Use the 'commit confirmed' command.
Automatically rolls back if not confirmed.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Use the 'commit confirmed' command.
The 'commit confirmed' command is the correct method because it allows an administrator to commit a candidate configuration with a confirmation timeout (default 10 minutes). If connectivity is lost and the commit is not confirmed within the timeout, Junos automatically reverts to the previous configuration, ensuring the device remains reachable.
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.
Use the 'commit check' command.
Why it's wrong here
This only validates syntax, not connectivity.
Use the 'commit synchronize' command.
Why it's wrong here
Used for dual Routing Engines, not for automatic rollback.
Use the 'rollback' command.
Why it's wrong here
Manual rollback, not automatic.
Use the 'commit confirmed' command.
Why this is correct
Automatically rolls back if not confirmed.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates confuse 'commit confirmed' with 'commit check' or 'rollback', not realizing that 'commit confirmed' is the only option that provides an automatic, time-based reversion mechanism specifically designed to prevent loss of connectivity.
Detailed technical explanation
The 'commit confirmed' command uses a timer (default 600 seconds) during which the administrator must issue 'commit confirm' to make the changes permanent. If the timer expires without confirmation, Junos automatically performs a 'rollback 1' to revert to the previous active configuration. This is particularly useful for remote management scenarios where a misconfiguration could lock out the administrator, as the automatic rollback restores connectivity without manual intervention.
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
Junos Configuration Basics — This question tests Junos Configuration Basics — Read the scenario before looking for a memorised answer..
The correct answer is: Use the 'commit confirmed' command. — The 'commit confirmed' command is the correct method because it allows an administrator to commit a candidate configuration with a confirmation timeout (default 10 minutes). If connectivity is lost and the commit is not confirmed within the timeout, Junos automatically reverts to the previous configuration, ensuring the device remains reachable.
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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