JN0-106 User Interfaces Practice Question
Which TWO statements are true about commit operations in Junos? (Choose two.)
⚠ Common exam trap
Many candidates confuse `commit confirmed` with a simple commit, or assuming that `rollback 0` triggers a reboot, which is a common misconception from other network operating systems where rollback might involve a reload.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The commit command requires the candidate configuration to be syntactically correct.
Option B is correct because the commit command validates the candidate configuration for syntax and semantic errors before merging it into the active configuration; if the candidate is not syntactically correct, the commit fails and the running configuration remains unchanged. Option C is correct because commit confirmed activates the candidate configuration on a trial basis and, if the operator does not issue a confirming commit within the default 10-minute window, Junos automatically rolls back to the previously active configuration. Option A is wrong because rollback 0 loads the last committed (active) configuration into the candidate, it does not reboot the device. Option D is wrong because commit check only validates the candidate configuration for syntax and commit-time errors without applying it to the running system. Option E is wrong because commit at schedules a configuration commit at a specified time, not a system reboot.
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 rollback 0 command will cause a system reboot.
Why it's wrong here
The rollback 0 command resets the candidate configuration to the currently active configuration, effectively discarding any uncommitted changes. It is purely a configuration-level operation that replaces the contents of the candidate; it does not restart the device or the management processes. A system reboot would require a separate command such as request system reboot, which is unrelated to configuration rollback. Therefore, this statement is false.
- ✓
The commit command requires the candidate configuration to be syntactically correct.
Why this is correct
The commit command in Junos performs a syntactic and, in some cases, semantic validation of the candidate configuration before it is activated. If the candidate contains syntax errors, the commit fails and the active configuration remains unchanged, preventing the device from being put into an invalid state. Thus, the requirement that the candidate be syntactically correct is a fundamental safeguard of the commit operation.
- ✓
The commit confirmed command will automatically revert to the previous configuration if not confirmed within the default 10 minutes.
Why this is correct
The commit confirmed command applies the candidate configuration and starts a confirmation timer that defaults to 10 minutes. If the administrator does not subsequently issue a commit (or commit confirm) to keep the change, Junos automatically reverts to the previous active configuration, restoring the device to its prior state. This is a safety mechanism for remote or risky changes, ensuring that loss of connectivity does not leave the device in an unmanageable configuration.
- ✗
The commit check command applies the configuration to the running system.
Why it's wrong here
The commit check command validates the candidate configuration for syntax correctness and proper Junos policy checks without activating it. It is essentially a dry run that reports errors but leaves the running configuration untouched. Only an explicit commit will apply the changes to the active configuration, so claiming that commit check applies changes is incorrect.
- ✗
The commit at command is used to schedule a system reboot.
Why it's wrong here
The commit at command schedules a commit operation to occur at a specified future time, allowing the candidate configuration to be activated later. It does not schedule a reboot; system reboots are performed with the request system reboot command, which is a separate operational action. Therefore, using commit at to schedule a reboot is a clear misconception.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This JN0-106 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 JN0-106 exam.