The answer is the operational mode command show system host-name. This command directly queries the Junos OS to retrieve and display the device’s configured hostname from the active configuration, confirming the router or switch’s identity on the network. On the JNCIA-Junos exam, this tests your ability to distinguish between operational commands that display system information versus configuration commands; a common trap is confusing it with show configuration system host-name, which shows the hostname only within the full configuration context. A reliable memory tip is to remember that “show system” commands are for real-time operational status, while “show configuration” commands are for static config files. For quick recall, think “host-name is a system property, so use show system host-name.”
JNCIA-JUNOS Junos OS Fundamentals Practice Question
This JNCIA-JUNOS practice question tests your understanding of junos os fundamentals. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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 command displays the current hostname of a Junos device?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Why wrong: This command shows hardware components, not the hostname.
C
show configuration system host-name
Why wrong: This command displays the hostname configuration, but requires configuration mode authority; the question asks for a command to view the hostname, which 'show system host-name' does in operational mode.
D
show system uptime
Why wrong: This shows system uptime and load, not the hostname.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
show system host-name
The command 'show system host-name' is the correct operational mode command to display the current hostname configured on a Junos device. It retrieves the hostname from the active configuration and displays it in the output, confirming the device's identity on the network.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
show system host-name
Why this is correct
This command shows the configured hostname.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
show chassis hardware
Why it's wrong here
This command shows hardware components, not the hostname.
✗
show configuration system host-name
Why it's wrong here
This command displays the hostname configuration, but requires configuration mode authority; the question asks for a command to view the hostname, which 'show system host-name' does in operational mode.
✗
show system uptime
Why it's wrong here
This shows system uptime and load, not the hostname.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse 'show configuration system host-name' (which shows the configuration stanza) with the operational command 'show system host-name', leading them to choose the configuration-oriented option instead of the direct operational display command.
Trap categories for this question
Command / output trap
This command shows hardware components, not the hostname.
Detailed technical explanation
How to think about this question
The hostname in Junos is stored under the 'system host-name' hierarchy in the configuration and is used for identification in syslog messages, CLI prompts, and routing protocols like BGP (via the 'router-id' or 'local-address' if derived). The 'show system host-name' command queries the management daemon (mgd) to retrieve the active hostname without requiring configuration mode access, making it a quick operational check for network engineers during troubleshooting or device inventory.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
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
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Junos OS Fundamentals — This question tests Junos OS Fundamentals — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: show system host-name — The command 'show system host-name' is the correct operational mode command to display the current hostname configured on a Junos device. It retrieves the hostname from the active configuration and displays it in the output, confirming the device's identity on the network.
What should I do if I get this JNCIA-JUNOS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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