JN0-106 Junos OS Fundamentals Practice Question
A technician is troubleshooting a device that has an inconsistent configuration. They need to revert to the configuration that was committed exactly two commits ago. Which command sequence accomplishes this?
⚠ Common exam trap
Test-takers frequently assume `rollback 2` alone immediately reverts the active configuration, forgetting that Junos requires an explicit `commit` to apply candidate changes.
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
✓
rollback 2 followed by commit
The `rollback 2` command reverts the candidate configuration to the state it was in two commits ago, but the change is not applied until a `commit` is issued. This two-step sequence (rollback followed by commit) is required to make the reverted configuration active. Without the commit, the device continues running the current active configuration.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
rollback 2
Why it's wrong here
rollback 2 changes only the candidate configuration, setting it to the state from the second-most-recent commit, but it does not affect the active running configuration. Without a subsequent commit, the device continues to operate with the current active configuration, so this command alone is insufficient. In the Junos CLI, rollback always operates on the candidate configuration and requires an explicit commit to make the change take effect.
- ✓
rollback 2 followed by commit
Why this is correct
rollback 2 followed by commit is the correct two-step procedure: rollback 2 loads the candidate configuration from the second previous commit (index 2), discarding any uncommitted changes, and commit then activates that candidate as the new active configuration. This fully reverts the device to the exact state it had two commits earlier, which is what the technician needs. Remember that rollback alone only stages the changes; only a commit applies them.
- ✗
commit confirmed 2
Why it's wrong here
commit confirmed 2 is unrelated to rolling back to commit number 2. It initiates a confirmed commit with a 2-minute timeout, meaning the configuration is committed temporarily and will automatically roll back to the previous configuration if the technician does not issue a commit confirm within two minutes. This mechanism is designed for safe remote commits, not for reverting to a specific earlier commit index. To revert to a prior commit, use rollback with the appropriate number and then commit.
- ✗
rollback 3
Why it's wrong here
rollback 3 would set the candidate configuration to the state from three commits ago, which is one commit further back than the intended target. The technician explicitly wants to revert to the configuration from two commits ago, so rollback 2 is the correct index. Using rollback 3 would bring the device to an older configuration and may introduce additional unwanted changes.
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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.