This JNCIA-JUNOS practice question tests your understanding of junos configuration basics. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
A junior engineer is asked to change the hostname of a Juniper device from 'Router-1' to 'Core-Router'. Which command sequence correctly commits the change?
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.
set system host-name Core-Router; commit
Correct syntax.
edit system; set host-name Core-Router; commit
Why wrong: Missing 'set' before 'host-name' in edit mode.
set system hostname Core-Router; commit
Why wrong: 'hostname' is not correct; it is 'host-name'.
set system host-name Core-Router; commit
Why wrong: 'host-name' is not a valid parameter; it is 'host-name' under 'system'.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
set system host-name Core-Router; commit
Option A is correct because the Junos CLI uses the 'set system host-name' command (with a hyphen in 'host-name') to change the device hostname, and 'commit' applies the change to the active configuration. The command sequence is syntactically valid and follows Junos configuration hierarchy.
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.
set system host-name Core-Router; commit
Why this is correct
Correct syntax.
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.
edit system; set host-name Core-Router; commit
Why it's wrong here
Missing 'set' before 'host-name' in edit mode.
set system hostname Core-Router; commit
Why it's wrong here
'hostname' is not correct; it is 'host-name'.
set system host-name Core-Router; commit
Why it's wrong here
'host-name' is not a valid parameter; it is 'host-name' under 'system'.
Common exam traps
The trap here is that Juniper uses 'host-name' with a hyphen, not 'hostname' as in Cisco IOS, and candidates often forget the hyphen or use the wrong hierarchy, leading them to select option B or C.
Detailed technical explanation
Under the hood, the 'host-name' parameter is defined under the [edit system] hierarchy in the Junos configuration schema, and the commit operation validates the entire candidate configuration before applying it. A subtle behavior is that changing the hostname does not affect the device's loopback address or routing protocols directly, but it does update the prompt and syslog messages, which can be critical for network monitoring and automation scripts that parse device identifiers.
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 Configuration Basics — This question tests Junos Configuration Basics — Read the scenario before looking for a memorised answer..
The correct answer is: set system host-name Core-Router; commit — Option A is correct because the Junos CLI uses the 'set system host-name' command (with a hyphen in 'host-name') to change the device hostname, and 'commit' applies the change to the active configuration. The command sequence is syntactically valid and follows Junos configuration hierarchy.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 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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