JN0-106 Junos Configuration Basics Practice Question
A Juniper device has multiple candidate configurations loaded. The administrator wants to discard all uncommitted changes and revert to the last committed configuration. Which command should be used?
⚠ Common exam trap
Many candidates confuse 'rollback 0' with 'rollback 1', thinking 0 means 'no rollback' or that a higher number is needed to revert changes, when in fact 0 discards uncommitted edits and 1 reverts the last commit.
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
✓
rollback 0
The 'rollback 0' command reverts the candidate configuration to the last committed configuration, discarding all uncommitted changes. In Junos, the rollback command uses a numeric index where 0 always refers to the most recently committed configuration, effectively undoing any uncommitted edits.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
rollback 0
Why this is correct
The `rollback 0` command reverts the candidate configuration to the last committed configuration by loading revision 0 from the configuration history, which always represents the most recently committed state. This directly satisfies the requirement to discard all uncommitted changes without affecting previously committed configurations, as rollback numbers increment with each commit and 0 is the fixed reference for the last committed configuration.
- ✗
delete configuration
Why it's wrong here
`delete configuration` is not a valid Junos CLI command in this context. The configuration-mode `delete` instruction removes a specific hierarchy or statement (for example, `delete interfaces ge-0/0/0`), not an entire configuration revision. Issuing it without a concrete path would fail or target the wrong section, and it would not consult the committed configuration history that `rollback 0` references, so it cannot safely discard all uncommitted changes.
- ✗
clear configuration
Why it's wrong here
In Junos, the `clear` command is intended for operational state, such as `clear interfaces statistics` or `clear log`, and there is no `clear configuration` command in either operational or configuration mode. The candidate configuration is a managed database with commit and rollback semantics, not a temporary counter that can be wiped via `clear`. Attempting `clear configuration` would produce a syntax error or be unrecognized, making it an invalid way to revert uncommitted changes.
- ✗
load override terminal
Why it's wrong here
`load override terminal` prompts the user to paste or type a complete configuration into the terminal, and it replaces the entire candidate configuration with that manually supplied data. It does not read from the device's committed configuration history; instead, it overwrites the candidate with whatever text is entered, which is rarely identical to the last committed state. Since the goal is to discard uncommitted changes and return to the last committed configuration, this command would require re-entering the entire configuration manually, unlike `rollback 0`, which restores it from the revision history.
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Same concept, more angles
1 more way this is tested on JN0-106
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A junior administrator wants to discard all uncommitted changes made in the current configuration session. Which command accomplishes this?
easy- A.commit check
- ✓ B.rollback 0
- C.load factory-default
- D.clear configuration
Why B: The `rollback 0` command reverts the candidate configuration to the active committed configuration, effectively discarding all uncommitted changes made during the current session. In Junos, configuration changes are stored in a candidate configuration until explicitly committed; `rollback 0` loads the last committed configuration (index 0) into the candidate, wiping out any uncommitted edits.
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.