JN0-106 Junos OS Fundamentals Practice Question
A network administrator needs to remove all configuration changes made since the last commit without affecting the current active configuration. Which command should be used?
⚠ Common exam trap
A common mix-up: candidates confuse `rollback 0` with `rollback 1`; candidates often think rollback 1 reverts to the last committed state, but rollback 0 is the correct way to discard uncommitted changes while preserving the active configuration.
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 currently active committed configuration, discarding all uncommitted changes without affecting the active configuration. This is the correct way to undo all modifications made since the last commit while keeping the running configuration intact.
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 1
Why it's wrong here
The `rollback 1` command reverts the candidate configuration to the state of the previous committed configuration, which effectively discards the last commit as well as any uncommitted changes. Since the goal is to eliminate only the uncommitted modifications while preserving the current active configuration, `rollback 1` is too broad—it would also undo the most recent commit, potentially removing valid, committed settings. The correct command is `rollback 0`, which loads the last committed configuration without sacrificing any committed state.
- ✗
deactivate
Why it's wrong here
The `deactivate` command disables a specific configuration statement or hierarchy, causing the active configuration to ignore it after a commit, but the text remains in the candidate configuration. It does not remove uncommitted changes or revert the candidate to the last committed state, and it requires a commit to have any operational effect. Therefore, using `deactivate` to discard all uncommitted changes would be impossible—it would only toggle the status of individual statements, leaving the actual edits in place.
- ✓
rollback 0
Why this is correct
The `rollback 0` command precisely addresses the requirement to discard uncommitted changes. When executed in configuration mode, it reverts the *candidate configuration* to the state of the *last committed configuration*. This action effectively removes all modifications made since the previous commit without impacting the *active configuration* currently running on the device. The active configuration remains unaffected because `rollback 0` operates solely on the pending configuration, ensuring operational stability.
- ✗
delete
Why it's wrong here
The `delete` command selectively removes a named configuration element from the candidate configuration, but it does not revert the entire configuration to a previous state and requires a commit to make the deletion active. To discard all uncommitted changes with `delete`, an administrator would have to manually track and remove every edited statement, which is tedious, error-prone, and may miss entire subtrees or leaves. Additionally, `delete` only removes; it cannot restore previously committed data, so it is not a suitable mechanism for rolling back uncommitted modifications.
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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.