JN0-106 rollback 0 Practice Question

A network administrator accidentally deleted a vital part of the configuration while in configuration mode. They need to revert to the previous configuration without losing recent changes that are correct. Which action should they take?

⚠ Common exam trap

The trap is that candidates often confuse 'rollback 0' (reverts to current active config) with 'rollback 1' (reverts to previous config). While 'rollback 1' might seem like it goes back one step, it could discard recently committed changes. The correct approach to undo an uncommitted deletion while preserving committed correct changes is to use 'rollback 0'.

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 0

The 'rollback 0' command reverts the candidate configuration to the most recently committed configuration (the current active configuration), discarding any uncommitted changes. This allows the administrator to undo the accidental deletion without affecting any recently committed correct changes, as those are already part of the active configuration. Option B, 'rollback 1', would revert to the previous commit, which could remove recently committed correct changes if they were made in the most recent commit. Therefore, 'rollback 0' is the safer choice when you want to preserve correct changes that have already been committed.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
deactivate
Why it's wrong here
Deactivating a configuration statement marks it inactive in the candidate configuration, but it does not restore or resurrect statements that were deleted. If the vital part was already removed with a delete command, there is no statement left to deactivate. Moreover, deactivate is an editing operation that changes the configuration, not a rollback mechanism, so it cannot undo an accidental deletion. It would only disable a still-present statement, which does not match the scenario.
✗
rollback 1
Why it's wrong here
Rollback 1 reverts the candidate configuration to the configuration that was committed at the previous commit, effectively undoing all changes made in the last commit. If the correct changes were committed in that last commit, this rollback would discard them as well, which directly violates the requirement to preserve those changes. The accidental deletion described is uncommitted, so rolling back to a committed revision overshoots and removes the good, committed configuration that should be kept.
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delete
Why it's wrong here
The delete command is used to remove configuration statements from the candidate or active configuration. In this scenario, the vital part was already accidentally deleted, so issuing another delete would either delete nothing or attempt to delete additional parts, potentially causing further damage. Delete is an editing operation that moves forward, not a rollback, so it cannot recover the original configuration. It is the opposite of the restoration needed here.
✓
rollback 0
Why this is correct
Rollback 0 resets the candidate configuration to match the current active committed configuration, discarding any uncommitted changes. Because the accidental deletion was never committed, this command reverts that deletion while leaving all previously committed correct changes intact. This is exactly the requirement: undo the uncommitted mistake without affecting the committed configuration. It is the standard way to abandon a set of uncommitted edits in Junos.

Go deeper

JN0-106 rollback 0 Practice Question

Why each option matters

Option-by-option breakdown

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