JN0-106 User Interfaces Practice Question
A network engineer needs to revert to the configuration that was committed two commits ago. Which rollback number should they use?
⚠ Common exam trap
Test-takers frequently confuse the rollback number with the number of commits to revert, where candidates might mistakenly think rollback 1 means one commit ago (which is correct) but then incorrectly apply that logic to two commits ago by choosing rollback 1 instead of rollback 2.
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
The rollback command in Junos OS allows reverting to a previously committed configuration. The rollback number corresponds to the number of commits ago, starting with rollback 0 for the most recent commit, rollback 1 for the commit before that, and so on. Therefore, to revert to the configuration committed two commits ago, the correct rollback number is 2.
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
In Junos, rollback 0 refers to the current active configuration that the device is running, not a prior configuration. Issuing "rollback 0" simply reloads the candidate configuration to match the current committed configuration, effective immediately, which would not undo the most recent changes. Since the goal is to revert to a configuration saved two commits earlier, rollback 0 does not achieve that, as it only resets to the present state without any historical navigation.
- ✓
rollback 2
Why this is correct
Junos maintains up to 50 previous committed configurations in its rollback log. The rollback command uses an index where 0 is the current active configuration, 1 is the most recent previous commit, and 2 is the commit before that. Thus, "rollback 2" precisely stages the configuration from two commits ago into the candidate, allowing the engineer to then commit it and revert to that earlier state.
- ✗
rollback 1
Why it's wrong here
The rollback index 1 points to the immediately preceding committed configuration, not the one two commits ago. Selecting "rollback 1" would only undo the last commit and return to the state one configuration change earlier, which may not fully undo the two-step change that the engineer intends to revert. To reach two commits back, the correct index must be 2 because the indices count backward from the current running configuration.
- ✗
rollback 3
Why it's wrong here
A rollback index of 3 would stage the configuration from three commits ago, which goes further back in the commit history than required. Applying this would discard not only the two most recent commits but also an additional earlier commit, potentially losing configuration changes that should remain in place. Since the engineer specifically needs the state from two commits ago, using rollback 3 overcorrects the rollback and is not the accurate target.
Go deeper
Related to this question
About these practice questions
One of 326 original JN0-106 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
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.