This JNCIA-JUNOS practice question tests your understanding of user interfaces. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
You are a network administrator for a large service provider. You have a Juniper MX960 that serves as a core router. The router uses a configuration with many apply-groups to streamline management. Recently, you added a new apply-group for interface-specific policies. After committing, several interfaces stopped passing traffic due to incorrect policy application. You need to quickly revert to the previous configuration without losing other valid changes made by other engineers in the same commit. The previous configuration is stored as rollback 1. However, rollback 1 contains configuration that does not include the new apply-group but also includes other valid changes from the last commit. You want to restore the configuration to exactly the state before the last commit (the rollback 1 state). Which command should you use?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
load override rollback 1 and commit
Option B is correct because 'load override rollback 1' replaces the entire candidate configuration with the exact contents of rollback 1, which is the state before the last commit. This allows you to revert the problematic apply-group change while preserving all other valid changes that were part of that same rollback snapshot. A subsequent 'commit' then activates this configuration, effectively undoing only the last commit without affecting earlier valid changes.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 and commit check
Why it's wrong here
commit check only validates; it does not apply.
✓
load override rollback 1 and commit
Why this is correct
This replaces the candidate with rollback 1, then commits it.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
rollback 0 and then commit
Why it's wrong here
rollback 0 sets candidate to current active config, which includes the problem.
✗
request system configuration rescue save and then load rescue
Why it's wrong here
Rescue config is for bootstrapping, not for this scenario.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is confusing 'rollback 0' (the current active configuration) with 'rollback 1' (the previous configuration), leading candidates to choose options that simply re-commit the current state instead of reverting to the prior one.
Trap categories for this question
Scenario analysis trap
Rescue config is for bootstrapping, not for this scenario.
Detailed technical explanation
How to think about this question
In Junos, rollback snapshots are stored as numbered files (0 through 49) in the /config directory, with rollback 1 always representing the configuration immediately before the most recent commit. The 'load override' command completely replaces the candidate configuration with the specified rollback file, discarding any uncommitted changes. This is distinct from 'load merge' or 'load replace', which would combine or patch the configuration, potentially reintroducing the unwanted apply-group if not carefully managed.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the JNCIA-JUNOS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
User Interfaces — This question tests User Interfaces — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: load override rollback 1 and commit — Option B is correct because 'load override rollback 1' replaces the entire candidate configuration with the exact contents of rollback 1, which is the state before the last commit. This allows you to revert the problematic apply-group change while preserving all other valid changes that were part of that same rollback snapshot. A subsequent 'commit' then activates this configuration, effectively undoing only the last commit without affecting earlier valid changes.
What should I do if I get this JNCIA-JUNOS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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