The answer is that the device automatically reverts to the previous active configuration. This happens because the 'commit confirmed 5' command activates the candidate configuration and starts a five-minute rollback timer; if the timer expires without a confirming 'commit' or 'commit check', Junos treats the timeout as a failure and triggers an automatic rollback to the last committed configuration. On the JNCIA-Junos exam, this scenario tests your understanding of commit confirmed timeout behavior and automatic rollback as a safety mechanism for remote maintenance. A common trap is assuming the device locks up or stays in the failed state—instead, Junos proactively restores connectivity by reverting the change. Remember the mnemonic “Confirm or Revert”: if you don’t confirm within the window, the router reverts to keep you connected.
JNCIA-JUNOS Junos Configuration Basics Practice Question
This JNCIA-JUNOS practice question tests your understanding of junos configuration basics. 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.
During a maintenance window, an engineer issues 'commit confirmed 5' but the change causes a connectivity loss. The engineer is unable to reconnect to the device before the timeout expires. What will happen?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The device automatically reverts to the previous active configuration.
The 'commit confirmed 5' command activates a candidate configuration and starts a 5-minute rollback timer. If the engineer does not issue a 'commit' or 'commit check' before the timer expires, Junos automatically reverts to the previously active configuration. This ensures the device returns to a known working state without manual intervention, preserving connectivity after the failed change.
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.
✗
The engineer must manually rollback using the rollback command.
Why it's wrong here
The rollback happens automatically after timeout.
✗
The change remains committed until the next reboot.
Why it's wrong here
Commit confirmed automatically rolls back if not confirmed.
✗
The device reloads with factory defaults.
Why it's wrong here
The device reverts to the previous configuration, not factory defaults.
✓
The device automatically reverts to the previous active configuration.
Why this is correct
Commit confirmed automatically rolls back after the timeout if not confirmed.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think a 'commit confirmed' requires a manual rollback command (Option A) or that the change persists until a reboot (Option B), but Junos automatically reverts the configuration upon timeout, making it a safety mechanism for remote changes.
Detailed technical explanation
How to think about this question
The 'commit confirmed' command uses a background timer (default 10 minutes, adjustable via the <minutes> parameter) that triggers a rollback to the previous active configuration if no confirmation is received. This is implemented in the Junos commit model, which maintains a history of committed configurations (up to 50 by default) and uses the 'rollback 1' candidate to restore the prior state. In real-world scenarios, this feature is critical during remote maintenance to prevent lockout; if the engineer loses connectivity, the device self-heals without requiring out-of-band access.
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.
TExam Day Tips
→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 exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Junos Configuration Basics — This question tests Junos Configuration Basics — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The device automatically reverts to the previous active configuration. — The 'commit confirmed 5' command activates a candidate configuration and starts a 5-minute rollback timer. If the engineer does not issue a 'commit' or 'commit check' before the timer expires, Junos automatically reverts to the previously active configuration. This ensures the device returns to a known working state without manual intervention, preserving connectivity after the failed change.
What should I do if I get this JNCIA-JUNOS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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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. A network engineer needs to make a change to a Junos device and ensure the change can be reverted if it causes issues. Which feature should be used?
easy
A.configure exclusive
✓ B.commit confirmed
C.commit check
D.rollback 0
Why B: The `commit confirmed` command allows an engineer to commit a configuration change with a timer (default 10 minutes). If the change causes issues and the engineer does not confirm the commit within the timer, the device automatically reverts to the previous active configuration. This provides a safety net to revert changes without manual intervention.
Last reviewed: Jun 24, 2026
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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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