- A
The rollback 0 command will cause a system reboot.
Why wrong: rollback 0 replaces candidate with active configuration, no reboot.
- B
The commit command requires the candidate configuration to be syntactically correct.
Commit will fail if there are syntax errors.
- C
The commit confirmed command will automatically revert to the previous configuration if not confirmed within the default 10 minutes.
Default timeout is 10 minutes.
- D
The commit check command applies the configuration to the running system.
Why wrong: commit check only validates syntax; it does not apply changes.
- E
The commit at command is used to schedule a system reboot.
Why wrong: commit at schedules a commit, not a reboot.
Quick Answer
The answer is that the commit confirmed command will automatically revert to the previous configuration if not confirmed within the default 10 minutes, and the commit command requires the candidate configuration to pass syntax and commit script checks before it is applied. These two statements are true because Junos enforces configuration validation as a core safety mechanism: the candidate configuration is checked for errors and script compliance before it becomes active, preventing invalid or broken changes from disrupting the network. On the JNCIA-Junos exam, commit operations are a frequent topic, testing your understanding of how Junos separates the candidate and active configurations, and the specific behavior of commit confirmed as a rollback safety net. A common trap is assuming commit confirmed uses a 5-minute timer or that syntax checks are optional, but the default is 10 minutes and checks are mandatory. Memory tip: think of commit confirmed as a “10-minute safety net” that catches you if you forget to confirm, while the syntax check is the gatekeeper that stops bad configs from ever going live.
JNCIA-JUNOS User Interfaces Practice Question
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.
Which TWO statements are true about commit operations in Junos? (Choose two.)
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
The commit command requires the candidate configuration to be syntactically correct.
Option B is correct because the `commit` command in Junos requires the candidate configuration to pass syntax and commit script checks before it is applied to the running system. If the configuration contains errors, the commit will fail, ensuring that only valid configurations are activated.
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.
- ✗
The rollback 0 command will cause a system reboot.
Why it's wrong here
rollback 0 replaces candidate with active configuration, no reboot.
- ✓
The commit command requires the candidate configuration to be syntactically correct.
Why this is correct
Commit will fail if there are syntax errors.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
The commit confirmed command will automatically revert to the previous configuration if not confirmed within the default 10 minutes.
Why this is correct
Default timeout is 10 minutes.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The commit check command applies the configuration to the running system.
Why it's wrong here
commit check only validates syntax; it does not apply changes.
- ✗
The commit at command is used to schedule a system reboot.
Why it's wrong here
commit at schedules a commit, not a reboot.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is confusing `commit confirmed` with a simple commit, or assuming that `rollback 0` triggers a reboot, which is a common misconception from other network operating systems where rollback might involve a reload.
Detailed technical explanation
How to think about this question
The `commit confirmed` command (option C) uses a default confirmation timeout of 10 minutes, after which the system automatically reverts to the previous configuration if not confirmed via a subsequent `commit` command. This is useful for remote access scenarios where a misconfiguration could lock out the administrator, providing a safety net. Under the hood, Junos stores configuration versions in numbered rollback slots (0–49), and `rollback 0` simply loads the last committed configuration into the candidate, with no effect on the running system until a commit is issued.
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 — study guide chapter
Learn the concepts, then practise the questions
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FAQ
Questions learners often ask
What does this JNCIA-JUNOS question test?
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: The commit command requires the candidate configuration to be syntactically correct. — Option B is correct because the `commit` command in Junos requires the candidate configuration to pass syntax and commit script checks before it is applied to the running system. If the configuration contains errors, the commit will fail, ensuring that only valid configurations are activated.
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more ways this is tested on JNCIA-JUNOS
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which TWO statements about the 'commit' operation in Junos OS are correct?
medium- A.It can be rolled back using the 'rollback 0' command.
- ✓ B.It applies the candidate configuration to the active configuration.
- ✓ C.It saves the configuration to the juniper.conf.gz file.
- D.It automatically reboots the device if system changes are made.
- E.It requires the configuration to be validated with 'commit check' first.
Why B: Option B is correct because the 'commit' operation in Junos OS applies the candidate configuration to the active configuration, making the changes effective immediately. This is the fundamental purpose of the commit command, which activates the pending configuration changes stored in the candidate configuration database.
Last reviewed: Jun 24, 2026
This JNCIA-JUNOS 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 JNCIA-JUNOS exam.
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