JNCIA-JUNOS Junos Configuration Basics Practice Question
This JNCIA-JUNOS practice question tests your understanding of junos configuration basics. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
An engineer needs to apply a configuration change to the Junos device that must survive a reboot. Which configuration mode command should be used to save the changes?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
commit
The 'commit' command is the standard way to apply a candidate configuration to the active configuration in Junos. When you issue 'commit', the changes are saved to the /config/juniper.conf.gz file, which is loaded upon reboot, ensuring the configuration survives a restart.
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.
✓
commit
Why this is correct
'commit' saves the candidate configuration into the active configuration, which survives a reboot.
Related concept
Read the scenario before looking for a memorised answer.
✗
commit confirmed
Why it's wrong here
'commit confirmed' requires a confirming commit within the rollback time or the configuration rolls back.
✗
commit synchronize
Why it's wrong here
'commit synchronize' is used on dual RE systems to copy the config to both REs but does not affect persistence beyond a normal commit.
✗
commit check
Why it's wrong here
'commit check' validates the configuration syntax but does not save it.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse 'commit' with 'commit confirmed', thinking the latter is required for persistence, but 'commit confirmed' is specifically designed for safe rollback during maintenance windows, not for permanent saves.
Detailed technical explanation
How to think about this question
When 'commit' is executed, Junos writes the candidate configuration to the active database (juniper.conf.gz) and also creates a backup file (juniper.conf.1.gz) for rollback. The system then loads the new configuration into the kernel's data structures, making it the operational configuration. In a real-world scenario, if an engineer forgets to commit after making changes, a reboot will revert to the last committed configuration, potentially causing service outages.
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.
Junos Configuration Basics — This question tests Junos Configuration Basics — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: commit — The 'commit' command is the standard way to apply a candidate configuration to the active configuration in Junos. When you issue 'commit', the changes are saved to the /config/juniper.conf.gz file, which is loaded upon reboot, ensuring the configuration survives a restart.
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.
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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.
Question Discussion
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