Quick Answer
The answer is rebooting the chassis, as this is a fundamental action performed in operational mode on a Junos device. Operational mode is the default CLI state used for monitoring, troubleshooting, and managing the device’s current state, including executing commands like ping, traceroute, and request system reboot, but it strictly prohibits configuration changes. On the JNCIA-Junos exam, this concept tests your ability to distinguish operational mode from configuration mode, where the latter uses commands like set or edit. A common trap is confusing reboot with configuration tasks—remember that operational mode handles live device actions, not persistent changes. A useful memory tip is to think of operational mode as the “driver’s seat” for running the device, while configuration mode is the “garage” for modifying its blueprint.
This JNCIA-JUNOS practice question tests your understanding of junos os fundamentals. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which THREE actions can be performed in operational mode on a Junos device?
Commit configuration changes
Why wrong: Commit is a configuration mode command.
Ping a remote host
Ping is an operational command.
Configure interface IP addresses
Why wrong: Interface configuration requires configuration mode.
View system logs
Log viewing is done in operational mode.
Reboot the chassis
Reboot is an operational command (request system reboot).
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Ping a remote host
Operational mode in Junos is used for monitoring, troubleshooting, and managing the device, not for making configuration changes. The 'ping' command is a standard operational mode command that sends ICMP echo requests to a remote host to test network connectivity, making option B correct.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Commit configuration changes
Why it's wrong here
Commit is a configuration mode command.
Ping a remote host
Why this is correct
Ping is an operational command.
Related concept
Read the scenario before looking for a memorised answer.
Configure interface IP addresses
Why it's wrong here
Interface configuration requires configuration mode.
View system logs
Why this is correct
Log viewing is done in operational mode.
Related concept
Read the scenario before looking for a memorised answer.
Reboot the chassis
Why this is correct
Reboot is an operational command (request system reboot).
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates familiar with Cisco IOS may mistakenly think that configuration commands like 'commit' or 'set interface' can be executed in operational mode, but Junos strictly enforces the separation between operational and configuration modes.
Trap categories for this question
Command / output trap
Commit is a configuration mode command.
Detailed technical explanation
Junos separates device operations into two primary modes: operational mode (indicated by a '>' prompt) for monitoring and troubleshooting, and configuration mode (indicated by a '#' prompt) for making changes to the active configuration. The 'ping' command in operational mode uses ICMP packets and can be fine-tuned with options like 'count', 'rapid', or 'do-not-fragment' to test specific network behaviors. Understanding this mode distinction is critical for efficient Junos administration, as attempting configuration changes in operational mode will result in an error.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the JNCIA-JUNOS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
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FAQ
Junos OS Fundamentals — This question tests Junos OS Fundamentals — Read the scenario before looking for a memorised answer..
The correct answer is: Ping a remote host — Operational mode in Junos is used for monitoring, troubleshooting, and managing the device, not for making configuration changes. The 'ping' command is a standard operational mode command that sends ICMP echo requests to a remote host to test network connectivity, making option B correct.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
This JNCIA-JUNOS 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 JNCIA-JUNOS exam.
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