JN0-106 Junos OS Fundamentals Practice Question
A network engineer is configuring a new Juniper device and needs to ensure that the configuration is saved persistently across reboots. Which command should be used?
⚠ Common exam trap
The trap here is that candidates familiar with Cisco IOS may mistakenly think `save` or `write memory` is the equivalent command, but Junos requires an explicit `commit` to persist changes.
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 activates the candidate configuration and saves it to the active configuration database, ensuring it persists across reboots. Without a commit, any changes made in candidate mode are lost when the device restarts.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
save
Why it's wrong here
In Junos, `save` is not a command for activating configuration changes; it is typically used within configuration mode to write the candidate configuration to a file (e.g., `/var/tmp/config`) for backup or archive. This action only copies the configuration text to the specified destination—it does not validate, activate, or persist the changes as the running configuration. Therefore, using `save` would leave the device running its previous active configuration and the changes vulnerable to loss.
- ✗
request system reboot
Why it's wrong here
`request system reboot` is a valid operational command that restarts the Junos device, but it never saves or activates the candidate configuration. If you have made configuration changes and only issued this command, those changes are discarded because they exist only in the candidate store until committed. A reboot loads the last committed configuration from the persistent store, so the device returns to the previous active state—it does not preserve uncommitted edits.
- ✗
show configuration
Why it's wrong here
The `show configuration` command displays the current active configuration (or, with the `| display` modifiers, the candidate configuration) as formatted text for inspection. It is purely read-only and performs no writes to any configuration database, so it cannot persist changes across reboots or alter the running state. This command is useful for verification, but it is not a substitute for committing configuration.
- ✓
commit
Why this is correct
The `commit` command is the only way to make candidate configuration changes active and permanent in Junos. It runs full configuration validation and, if successful, installs the candidate into the active configuration store, which is what loads at reboot. Because `commit` persists the changes to storage and activates them at once, it is the required final step after editing any configuration.
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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.