JN0-106 Junos Configuration Basics Practice Question
An administrator makes changes to the candidate configuration and wants to automatically revert to the previous configuration if the changes cause a loss of connectivity. Which method should be used?
⚠ Common exam trap
Many candidates confuse 'commit confirmed' with 'commit check' or 'rollback', not realizing that 'commit confirmed' is the only option that provides an automatic, time-based reversion mechanism specifically designed to prevent loss of connectivity.
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
✓
Use the 'commit confirmed' command.
The 'commit confirmed' command is the correct method because it allows an administrator to commit a candidate configuration with a confirmation timeout (default 10 minutes). If connectivity is lost and the commit is not confirmed within the timeout, Junos automatically reverts to the previous configuration, ensuring the device remains reachable.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use the 'commit check' command.
Why it's wrong here
The 'commit check' command performs a dry-run validation of the candidate configuration, checking syntax and resource availability without activating the changes. It never modifies the active configuration or sets any timer, so it cannot provide an automatic rollback if connectivity is lost. This makes it a useful pre-commit diagnostic but not a safety net for the described scenario.
- ✗
Use the 'commit synchronize' command.
Why it's wrong here
The 'commit synchronize' command is specifically designed for devices with dual Routing Engines, ensuring the same configuration is committed on both REs simultaneously. It does not implement any confirmation timer or automatic revert mechanism; it simply coordinates two separate commit operations. On a single-RE device, this command is not applicable and would not serve as an automatic rollback.
- ✗
Use the 'rollback' command.
Why it's wrong here
The 'rollback' command loads a previously committed configuration into the candidate configuration, but it only takes effect when an administrator manually executes it. It does not create a timed confirmation window or monitor for connectivity, so it cannot automatically revert an unconfirmed change. Relying on 'rollback' requires human intervention, which is exactly what the administrator wants to avoid during a remote session.
- ✓
Use the 'commit confirmed' command.
Why this is correct
The 'commit confirmed' command activates the candidate configuration immediately and starts a default 10-minute confirmation timer, after which the system automatically reverts to the prior configuration if no confirmation is received. The administrator can extend or shorten this window with the optional minutes argument and must issue 'commit confirm' to make the change permanent. This automatic rollback preserves the device's reachability, making it the ideal command for the scenario described.
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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.