Quick Answer
The answer is the `commit confirmed` command, which controls the automatic rollback timeout for configuration changes in Junos. This command applies a configuration change that will automatically revert to the previous configuration if not explicitly confirmed within a specified time period, defaulting to 10 minutes. The technical concept here is that `commit confirmed` creates a safety net: the engineer must re-issue a standard `commit` command before the timeout expires to make the changes permanent, preventing accidental lockout or misconfiguration. On the JNCIA-Junos exam, this tests your understanding of safe operational practices during remote device configuration, often appearing in scenario-based questions where an engineer is making risky changes. A common trap is confusing `commit confirmed` with `commit check` (which only validates syntax) or forgetting that the timeout is configurable with the `commit confirmed <minutes>` parameter. Memory tip: think of it as a “commit with a safety timer”—if you don’t confirm before the alarm rings, the router hits undo.
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.
When configuring a new Juniper router, an engineer needs to ensure that configuration changes are not automatically committed after a certain time if not explicitly confirmed. Which configuration parameter controls this?
commit check
Why wrong: Validates syntax but does not commit.
commit at
Why wrong: Schedules a commit at a specific time.
commit synchronize
Why wrong: Applies to multi-chassis systems.
commit confirmed
Requires confirmation; otherwise rolled back after timeout.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
commit confirmed
The 'commit confirmed' command is used to apply a configuration change that will automatically roll back to the previous configuration if not explicitly confirmed within a specified time period (default 10 minutes). This ensures that changes are not permanently applied unless the engineer verifies them, preventing accidental lockout or misconfiguration.
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.
commit check
Why it's wrong here
Validates syntax but does not commit.
commit at
Why it's wrong here
Schedules a commit at a specific time.
commit synchronize
Why it's wrong here
Applies to multi-chassis systems.
commit confirmed
Why this is correct
Requires confirmation; otherwise rolled back after timeout.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates often confuse 'commit confirmed' with 'commit at' or 'commit synchronize', thinking any time-based or dual-RE feature provides automatic rollback, but only 'commit confirmed' enforces a confirmation window to prevent permanent unverified changes.
Detailed technical explanation
When 'commit confirmed <minutes>' is issued, Junos creates a temporary rollback point and starts a timer. If the engineer does not issue a 'commit' (or 'commit check' followed by 'commit') before the timer expires, Junos automatically performs a 'rollback 0' to revert to the previous active configuration. This is particularly useful during remote management changes (e.g., modifying firewall filters or routing policies) where a loss of connectivity could otherwise leave the device in an unreachable state.
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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Junos Configuration Basics — study guide chapter
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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: commit confirmed — The 'commit confirmed' command is used to apply a configuration change that will automatically roll back to the previous configuration if not explicitly confirmed within a specified time period (default 10 minutes). This ensures that changes are not permanently applied unless the engineer verifies them, preventing accidental lockout or misconfiguration.
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 11, 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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