JN0-106 Junos Configuration Basics Practice Question
A network engineer wants to quickly restore the device to a known good configuration after a failed change. What is the recommended approach?
⚠ Common exam trap
Candidates often confuse 'rollback rescue' with 'rollback 0', mistakenly thinking the most recent committed configuration is always a safe fallback, but 'rollback 0' includes the failed change if it was committed, whereas 'rollback rescue' restores a deliberately saved known good state.
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 'rollback rescue' command.
The 'rollback rescue' command restores the device to the rescue configuration, which is a known good configuration saved explicitly for recovery after a failed change. The rescue configuration is stored as a separate file and is not affected by normal commit operations, making it the recommended approach for quick restoration.
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 'request system configuration rescue save' command.
Why it's wrong here
The 'request system configuration rescue save' command is used to store the currently active configuration as a rescue configuration in the rescue slot. This is a save operation, not a restore: it captures a known-good snapshot for future recovery. Running it immediately before a problematic change would overwrite any previously saved rescue config, so it does not itself restore the device to a safe state, and it is the prerequisite command for later using 'rollback rescue'.
- ✗
Use the 'rollback 0' command.
Why it's wrong here
Running 'rollback 0' reverts to the most recently committed configuration. If the engineer has just committed a failed change, rollback 0 will reload exactly that same failed configuration into the candidate, because it is now the latest committed version. It does not reference the separately stored rescue configuration, so it cannot undo the damage unless the rescue config happens to be the last committed config. This command is useful for undoing an uncommitted session or a bad commit only if a prior good config is the last committed one, not for rescue restoration.
- ✓
Use the 'rollback rescue' command.
Why this is correct
The 'rollback rescue' command loads the previously saved rescue configuration from the rescue area into the candidate configuration. This is the correct restore mechanism because it explicitly retrieves the snapshot created via 'request system configuration rescue save'. The command does not automatically commit the change; the engineer must still run 'commit' to apply the rescued configuration to the active Janos configuration.
- ✗
Use the 'load override terminal' command.
Why it's wrong here
The 'load override terminal' command replaces the entire candidate configuration with configuration text that the user types or pastes into the terminal. It does not access any stored rescue configuration, so it cannot be used to restore a previously saved snapshot unless the user manually reproduces that configuration. This option is also interactive and error-prone in an emergency, as it discards the existing candidate, unlike 'rollback rescue' which retrieves a known-good file.
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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.