JN0-106 User Interfaces Practice Question
A user wants to ensure that a configuration change is applied across both Routing Engines in a dual-RE system. Which command must be used?
⚠ Common exam trap
Test-takers frequently confuse 'commit synchronize' with 'commit full' or 'commit confirmed', assuming any commit command applies to both REs, but only 'commit synchronize' explicitly ensures dual-RE consistency.
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 synchronize
The 'commit synchronize' command applies the candidate configuration to both Routing Engines simultaneously in a dual-RE system. This ensures configuration consistency across the master and backup RE, which is critical for high availability and seamless failover in Junos.
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 and-quit
Why it's wrong here
commit and-quit commits the candidate configuration on the current Routing Engine and immediately exits configuration mode. It performs a plain commit on the local RE only and does not replicate the configuration to the standby RE. For a dual-Routing Engine system, the user must explicitly use "commit synchronize" to propagate the change to both REs. Therefore, using this command would leave the standby RE with a different configuration, failing the requirement.
- ✗
commit confirmed
Why it's wrong here
commit confirmed schedules an automatic rollback after a default timeout of 10 minutes unless the user re-issues "commit confirm" to make the change permanent. It is a safety mechanism to prevent configuration lockouts, but it does not, by itself, distribute the configuration to a second Routing Engine. The "synchronize" option would have to be added (e.g., "commit confirmed synchronize") to also update both REs, but the plain command is incorrect for this scenario.
- ✗
commit full
Why it's wrong here
commit full is not a recognized Junos operational or configuration-mode command. The Junos commit commands include "commit", "commit check", "commit confirmed", "commit synchronize", and "commit and-quit", among others, but "full" is not a valid keyword. Attempting to use it would result in a syntax error on the Junos CLI. Hence it is not a viable way to apply a configuration change.
- ✓
commit synchronize
Why this is correct
commit synchronize is the correct command because it commits the candidate configuration on both Routing Engines in a single operation. The Junos OS first performs the commit on the local RE and then pushes the same configuration to the standby RE, verifying that both accept the change. This ensures configuration consistency across the control planes, which is essential for hitless failover and smooth operation in a dual-RE chassis.
Visual reference
Go deeper
Related to this question
About these practice questions
Courseiva writes every JN0-106 question from scratch — 326 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
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.