JN0-106 User Interfaces Practice Question
An administrator wants to navigate to the configuration mode to make changes to the device. Which command should be used?
⚠ Common exam trap
The trap here is that Cisco engineers often confuse 'configure terminal' (Cisco IOS) with JUNOS commands, mistakenly thinking 'set' or 'edit' are the entry points to configuration mode, when in fact 'configure' is the required command to enter configuration mode from operational mode.
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
✓
configure
The correct command to enter configuration mode on a Juniper device is 'configure'. This command transitions the CLI from operational mode to configuration mode, allowing the administrator to make changes to the device's configuration. In JUNOS, the CLI has two distinct modes: operational mode (for monitoring and troubleshooting) and configuration mode (for modifying the active or candidate configuration).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
set
Why it's wrong here
The 'set' command is a configuration-mode directive used to add or modify parameter values within the active configuration hierarchy, such as 'set interfaces ge-0/0/0 unit 0 family inet address 192.0.2.1/24'. It cannot be executed from operational mode to transition into configuration mode; attempting to do so yields a 'syntax error' or 'command not found' because 'set' only has meaning after the CLI has already entered the configuration context. Therefore, 'set' is incorrect for this task.
- ✗
edit
Why it's wrong here
The 'edit' command is a configuration-mode navigation utility that moves you between hierarchy levels in the configuration tree, for example, 'edit interfaces' or 'edit system syslog'. It presupposes that you are already inside configuration mode and does not itself perform the mode transition from operational mode to configuration mode. While 'edit' may appear in operational mode in some contexts, it does not invoke the 'configure' functionality that opens the configuration database, making it the wrong choice.
- ✓
configure
Why this is correct
The 'configure' command is the correct Junos operational-mode command used to enter configuration mode, where the active or candidate configuration can be viewed and manipulated. When you type 'configure' at the operational prompt, the CLI switches to the configuration hierarchy, and the prompt changes to 'edit' (e.g., 'user@router#'). Variants like 'configure exclusive' or 'configure private' provide additional control over locking or private copies, but the base command is the standard entry point. Thus, 'configure' is the right answer.
- ✗
cli
Why it's wrong here
The 'cli' command is a shell-level command that starts the Junos CLI from a Unix shell or login session, not a command used within the CLI itself to enter configuration mode. In the operational mode of the CLI, typing 'cli' produces an error because it is not a recognized operational command, and it has no effect on transitioning to configuration mode. Since the administrator is already in the CLI and wants to reach configuration mode, 'cli' is irrelevant and incorrect.
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Same concept, more angles
2 more ways 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. An engineer needs to view the current active configuration of a Junos device without making any changes. Which CLI mode should they use?
easy- ✓ A.Operational mode
- B.Privileged mode
- C.Configuration mode
- D.Exclusive configuration mode
Why A: Operational mode is the default CLI mode in Junos, used for monitoring, troubleshooting, and viewing the current active configuration without making any changes. Commands in this mode are read-only and do not modify the device's configuration. The active configuration is the one currently running on the device, and it can be viewed using commands like 'show configuration' in operational mode.
Variation 2. Refer to the exhibit. An engineer configures a new IPv6 address on ge-0/0/0 unit 0 by entering the following commands in configuration mode: set interfaces ge-0/0/0 unit 0 family inet6 address 2001:db8::2/64 commit After the commit, the engineer runs 'show interfaces terse ge-0/0/0' and sees only the two original addresses. What is the most likely cause?
hard- A.The engineer used 'commit' instead of 'commit confirmed'.
- ✓ B.The engineer did not enter configuration mode before running the 'set' command.
- C.Junos only allows one IPv6 address per interface.
- D.The 'set' command requires the 'add' keyword to add a second address.
Why B: The engineer likely ran the 'set' command from operational mode (e.g., at the '>' prompt) rather than from configuration mode (e.g., at the '#' prompt). In Junos, 'set' commands only take effect when entered in configuration mode; if entered in operational mode, they are silently ignored or produce an error, and the configuration is not modified. Since the engineer saw no new address after commit, the 'set' command was never applied to the candidate configuration.
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.