Quick Answer
The answer is `arp -n | grep 192.168.1.1`. This command works because `arp -n` displays the system’s ARP cache in numeric format, disabling reverse DNS lookups to ensure raw IP addresses appear in the output, and piping it through `grep 192.168.1.1` filters the cache to show only the entry for that specific IP. On the LPIC-2 exam, this tests your ability to troubleshoot Layer 2 connectivity by inspecting the ARP table, a common task for network diagnostics. A frequent trap is forgetting the `-n` flag: without it, `arp` may perform hostname lookups, causing `grep` to miss the IP if it resolves to a name, or slowing down the output. To remember, think “numeric grep” — the `-n` keeps addresses raw so your filter works reliably.
This LPIC-2 practice question tests your understanding of advanced networking configuration. 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.
An administrator wants to check the ARP cache for a specific IP address 192.168.1.1. Which command will display the ARP entry for that address?
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.
ip neigh show 192.168.1.1
Why wrong: The correct syntax is 'ip neigh show | grep 192.168.1.1'; ip neigh show alone shows all.
arp -a 192.168.1.1
Why wrong: arp -a shows all entries with hostnames; to see specific, use arp -n and grep.
arp -n | grep 192.168.1.1
This filters the ARP cache for the specific IP.
route -n
Why wrong: This shows routing table, not ARP cache.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
arp -n | grep 192.168.1.1
Option C is correct because `arp -n` displays the ARP cache in numeric format, and piping it through `grep 192.168.1.1` filters the output to show only the entry for that specific IP address. The `-n` flag prevents reverse DNS lookups, ensuring the output contains raw IP addresses, which is essential for reliable filtering.
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.
ip neigh show 192.168.1.1
Why it's wrong here
The correct syntax is 'ip neigh show | grep 192.168.1.1'; ip neigh show alone shows all.
arp -a 192.168.1.1
Why it's wrong here
arp -a shows all entries with hostnames; to see specific, use arp -n and grep.
arp -n | grep 192.168.1.1
Why this is correct
This filters the ARP cache for the specific IP.
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.
route -n
Why it's wrong here
This shows routing table, not ARP cache.
Common exam traps
The trap here is that candidates often assume `arp -a` with an IP address works universally, but on Linux, `-a` expects a hostname and may fail silently or require DNS resolution, whereas `arp -n` with `grep` reliably filters numeric output without relying on name resolution.
Trap categories for this question
Command / output trap
The correct syntax is 'ip neigh show | grep 192.168.1.1'; ip neigh show alone shows all.
Detailed technical explanation
The ARP cache (neighbor table) maps IPv4 addresses to MAC addresses on a local network. The `arp` command reads from `/proc/net/arp` (or uses netlink sockets), while `ip neigh` uses the netlink interface directly. In real-world scenarios, using `arp -n` with `grep` is a quick troubleshooting method to verify if a specific IP has a resolved MAC address, which is critical for diagnosing Layer 2 connectivity issues.
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 LPIC-2 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
Advanced Networking Configuration — This question tests Advanced Networking Configuration — Read the scenario before looking for a memorised answer..
The correct answer is: arp -n | grep 192.168.1.1 — Option C is correct because `arp -n` displays the ARP cache in numeric format, and piping it through `grep 192.168.1.1` filters the output to show only the entry for that specific IP address. The `-n` flag prevents reverse DNS lookups, ensuring the output contains raw IP addresses, which is essential for reliable filtering.
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 LPIC-2 practice question is part of Courseiva's free LPI 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 LPIC-2 exam.
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