JN0-106 Rollback configuration Practice Question

Exhibit

Refer to the exhibit.
user@router> show system commit
0   2025-03-20 10:15:23 UTC by admin via cli
1   2025-03-20 09:45:10 UTC by root via cli (confirmed)
2   2025-03-19 14:30:00 UTC by admin via cli

Refer to the exhibit. The network administrator made a change that caused connectivity loss. They need to revert to the configuration before the most recent commit. Which command would accomplish this?

⚠ Common exam trap

Many candidates mistakenly believe that rollback 0 undoes the last change. However, rollback 0 loads the most recent committed configuration—the one that caused the connectivity loss—so it would reload the problem, not fix it. To revert to the configuration before the last commit, you must use rollback 1.

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 1

In Junos, rollback numbers are stored with 0 being the most recent committed configuration. To revert to the configuration before the most recent commit, you need to load the configuration that was active before that change. That is rollback 1, which represents the second most recent commit. Using rollback 0 would load the configuration that caused the issue, not fix it.

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 0
Why it's wrong here
rollback 0 reloads the most recently committed configuration into the candidate, which in this case is the same faulty configuration that caused the connectivity loss. It does not revert any changes; at best, it discards uncommitted candidate edits. Since the damage is already committed, rollback 0 provides no recovery benefit and would leave the network in its broken state.
✗
rollback 3
Why it's wrong here
rollback 3 would load the configuration from four commits ago, not the immediately preceding one. Since the connectivity loss was caused by the most recent commit, only rollback 1 is the precise fix. Using rollback 3 also discards three later sets of configuration changes, potentially removing unrelated valid settings and causing additional outages.
✗
rollback 2
Why it's wrong here
rollback 2 reverts to the configuration saved two commits prior, meaning it undoes both the latest problematic change and one earlier, previously working change. This is overly broad and would restore a configuration that is not only missing the intended fix but also lacking other legitimate modifications. The correct choice is rollback 1, which goes back exactly one commit, so rollback 2 is too far back and does not match the scope of the fault.
✓
rollback 1
Why this is correct
rollback 1 loads the configuration that was committed before the most recent commit. Because the administrator's latest change caused the connectivity loss, this returns the network to the exact working state immediately prior to that change. It is the only rollback target that precisely reverts the faulty modification while preserving all earlier configuration data.

Go deeper

JN0-106 Rollback configuration Practice Question

Exhibit

Why each option matters

Option-by-option breakdown

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