JN0-106 Junos Configuration Basics Practice Question
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?
⚠ Common exam trap
A common mix-up: candidates 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.
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
✓
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.
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
The 'commit' command permanently activates the candidate configuration by copying it into the active configuration and applying it to the routing and forwarding planes. It also writes the configuration to non-volatile storage (e.g., flash), ensuring it survives a reboot or power cycle. This is the standard, definitive way to make configuration changes persistent in Junos.
- ✗
commit confirmed
Why it's wrong here
The 'commit confirmed' command initially installs the candidate configuration but starts a rollback timer (default 10 minutes, adjustable) during which the change is active. If no subsequent confirmation commit is issued before the timer expires, Junos automatically reverts to the previous configuration, preventing configuration lockouts. It does not provide permanent persistence unless explicitly confirmed; it is a temporary safety mechanism.
- ✗
commit synchronize
Why it's wrong here
The 'commit synchronize' command is used specifically on dual Routing Engine systems to commit the candidate configuration on both REs at the same time, ensuring configuration consistency across the chassis. It does not affect the persistence model—the configuration is still saved to the active store just like a normal commit, and it remains persistent across reboots. Its purpose is operational synchronization, not a distinct form of durable commit.
- ✗
commit check
Why it's wrong here
The 'commit check' command performs a validation of the candidate configuration for syntax and semantic errors but does not activate it or write it to the active configuration. Any errors are reported back to the user, and the candidate configuration remains untouched, allowing corrections before a final commit. Since it does not modify the active configuration, nothing is saved or persisted across a reboot.
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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.