Quick Answer
The correct command is `show arp instance <instance-name>`. This is the precise Junos OS syntax because routing instances in Juniper devices create isolated Layer 3 forwarding domains, each maintaining its own independent ARP cache; the `instance` keyword directs the command to query the ARP table belonging specifically to that named routing instance rather than the default master instance. On the JNCIA-Junos exam, this question tests your understanding of how Junos separates control plane resources across virtual routing and forwarding (VRF) instances, a common configuration in enterprise and service provider networks. A frequent trap is confusing this with `show arp` (which shows only the default instance) or `show arp routing-instance` (which is incorrect syntax). To remember, think of the pattern: for any per-instance show command in Junos, the keyword `instance` follows the object—so `show arp instance`, `show route instance`, `show interfaces instance`—making it a reliable memory anchor for the exam.
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.
A device is configured with multiple routing instances. An engineer needs to view the ARP table for a specific routing instance. Which command should be used?
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.
show arp routing-instance <instance-name>
Why wrong: D is not the correct syntax.
show arp
Why wrong: A shows default instance only.
show arp instance <instance-name>
B displays ARP for the specified instance.
show route table <instance-name>.inet.0
Why wrong: C shows routes, not ARP.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
show arp instance <instance-name>
Option C is correct because the `show arp instance <instance-name>` command is the Junos OS syntax to display the ARP table for a specific routing instance. In Junos, routing instances create separate forwarding tables, and the ARP cache is per-instance; this command targets the instance's ARP entries directly.
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.
show arp routing-instance <instance-name>
Why it's wrong here
D is not the correct syntax.
show arp
Why it's wrong here
A shows default instance only.
show arp instance <instance-name>
Why this is correct
B displays ARP for the specified instance.
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 route table <instance-name>.inet.0
Why it's wrong here
C shows routes, not ARP.
Common exam traps
The trap here is that candidates often confuse the Junos command syntax with Cisco IOS, where `show arp vrf <name>` is used, leading them to incorrectly choose option A (`show arp routing-instance`) instead of the correct Junos syntax `show arp instance`.
Trap categories for this question
Command / output trap
A shows default instance only.
Detailed technical explanation
Junos maintains a separate ARP cache for each routing instance, as each instance has its own Layer 3 forwarding context. The `show arp instance` command queries the kernel's ARP table for that specific instance, which is critical in multi-tenant or VRF-like designs where overlapping IP addresses exist. For example, in a Layer 3 VPN scenario, checking ARP per instance ensures correct neighbor resolution within the correct virtual routing and forwarding (VRF) domain.
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
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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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: show arp instance <instance-name> — Option C is correct because the `show arp instance <instance-name>` command is the Junos OS syntax to display the ARP table for a specific routing instance. In Junos, routing instances create separate forwarding tables, and the ARP cache is per-instance; this command targets the instance's ARP entries directly.
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 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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