The answer is that the 'commit confirmed' command allows an administrator to test a configuration change with an automatic rollback if confirmation is not received. This works by applying the candidate configuration and starting a timer, defaulting to ten minutes; if the administrator does not issue a subsequent 'commit' command before the timer expires, Junos OS automatically reverts to the previous active configuration. On the JNCIA-Junos exam, this command tests your understanding of safe remote administration, often appearing in scenarios where a misconfigured interface could lock out an engineer. A common trap is confusing 'commit confirmed' with a simple 'commit'—remember that without the confirmation, the rollback is automatic, not optional. Memory tip: think of it as a "safety net" for your network changes, where the timer is your lifeline to either confirm or let the system catch you.
JNCIA-JUNOS Junos OS Fundamentals Practice Question
This JNCIA-JUNOS practice question tests your understanding of junos os fundamentals. 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.
What is the purpose of the 'commit confirmed' command in Junos OS?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
It allows the administrator to test a configuration change with automatic rollback if confirmation is not received
The 'commit confirmed' command in Junos OS applies a candidate configuration change and starts a confirmation timer (default 10 minutes). If the administrator does not issue a 'commit' command before the timer expires, the system automatically rolls back to the previous active configuration. This allows safe testing of changes, especially over remote connections, preventing lockout if the change breaks connectivity.
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.
✗
It compares the candidate configuration with the active configuration
Why it's wrong here
That is done with 'show | compare'.
✓
It allows the administrator to test a configuration change with automatic rollback if confirmation is not received
Why this is correct
This is the primary use: to safely apply changes and revert if connectivity is lost.
Related concept
Read the scenario before looking for a memorised answer.
✗
It permanently saves the candidate configuration to the startup configuration
Why it's wrong here
Commit saves to active, but 'commit confirmed' is temporary with auto-rollback.
✗
It confirms that a previous commit was successful
Why it's wrong here
That is not its function; it is a proactive rollback mechanism.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse 'commit confirmed' with a simple confirmation prompt or a verification step, when in fact it is a timed rollback mechanism designed to prevent lockout during remote configuration changes.
Trap categories for this question
Command / output trap
That is done with 'show | compare'.
Detailed technical explanation
How to think about this question
Under the hood, 'commit confirmed' sets a timer (configurable with the 'confirm' option, e.g., 'commit confirmed 5' for 5 minutes) and marks the candidate configuration as a 'confirmed commit'. If the timer expires without a subsequent 'commit', the Junos kernel triggers an automatic rollback to the previous configuration by reverting to the last committed configuration file stored in /config/juniper.conf.gz. This is particularly useful when making changes to management interfaces, firewall filters, or routing protocols over a remote SSH session, as a loss of connectivity will not permanently lock the administrator out.
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 OS Fundamentals — This question tests Junos OS Fundamentals — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: It allows the administrator to test a configuration change with automatic rollback if confirmation is not received — The 'commit confirmed' command in Junos OS applies a candidate configuration change and starts a confirmation timer (default 10 minutes). If the administrator does not issue a 'commit' command before the timer expires, the system automatically rolls back to the previous active configuration. This allows safe testing of changes, especially over remote connections, preventing lockout if the change breaks connectivity.
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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Question Discussion
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