- A
Check the routing table on the remote server.
Why wrong: The remote server is reachable from other hosts, so its routing is likely fine.
- B
Ping the remote server from another host on the same subnet to verify connectivity.
Why wrong: The problem states that other hosts can reach it, so this step is unnecessary.
- C
Traceroute to the remote server from the affected server.
Why wrong: While traceroute can help, the most direct isolation steps are ARP and firewall checks.
- D
Check iptables rules for any OUTPUT chain that might be dropping packets.
Local firewall rules can block outbound traffic even if routing is correct.
- E
Verify the ARP cache on the server for the default gateway.
If the ARP entry for the gateway is missing or wrong, the server cannot send packets out.
Quick Answer
The answer is to verify the ARP cache on the server for the default gateway and check the iptables rules on the OUTPUT chain. This is correct because when other hosts on the same subnet can reach the remote host but the affected server cannot, the problem is isolated to that specific server’s local configuration rather than a routing or network-wide issue. The ARP cache may contain a stale or incorrect entry for the default gateway, preventing proper Layer 2 forwarding, while iptables OUTPUT rules can silently drop outbound packets destined for 192.168.1.50 without impacting other hosts. On the LPIC-2 exam, this scenario tests your ability to troubleshoot asymmetric connectivity problems where routing is properly configured, often trapping candidates who jump to checking routing tables or DNS first. Remember the memory tip: “When others reach but yours can’t, check ARP and the firewall’s chant.”
LPIC-2 Advanced Networking Configuration Practice Question
This LPIC-2 practice question tests your understanding of advanced networking configuration. 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 TWO network diagnostic steps should be performed to isolate a problem where a Linux server (IP 10.0.0.10/24) cannot reach a remote server (IP 192.168.1.50/24) while other hosts on the same subnet can reach it? Assume routing is properly configured.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Check iptables rules for any OUTPUT chain that might be dropping packets.
Option D is correct because if the affected server can reach the remote server via other hosts on the same subnet, the issue is likely local to the affected server itself. Checking iptables rules on the OUTPUT chain can reveal whether a firewall rule is specifically dropping outbound packets destined for 192.168.1.50, which would not affect other hosts on the same subnet. This is a common cause of asymmetric connectivity problems where routing is otherwise properly configured.
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.
- ✗
Check the routing table on the remote server.
Why it's wrong here
The remote server is reachable from other hosts, so its routing is likely fine.
- ✗
Ping the remote server from another host on the same subnet to verify connectivity.
Why it's wrong here
The problem states that other hosts can reach it, so this step is unnecessary.
- ✗
Traceroute to the remote server from the affected server.
- ✓
Check iptables rules for any OUTPUT chain that might be dropping packets.
Why this is correct
Local firewall rules can block outbound traffic even if routing is correct.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Verify the ARP cache on the server for the default gateway.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume a routing issue (Option A or C) when the problem is actually a local firewall or ARP issue, because the symptom 'cannot reach' is frequently misattributed to routing rather than to host-specific packet filtering or layer-2 resolution failures.
Detailed technical explanation
How to think about this question
The iptables OUTPUT chain filters packets originating from the local host before they leave the network stack, so a rule dropping packets to a specific destination (e.g., -d 192.168.1.50 -j DROP) would block outbound traffic only from that server. The ARP cache for the default gateway is critical because if the server has a stale or incorrect ARP entry for the gateway (e.g., due to a duplicate IP or a failed neighbor discovery), it cannot send packets to the next hop, even if routing is correct; clearing the ARP cache (ip neigh flush) or checking with 'arp -n' can resolve this.
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 network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
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.
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Advanced Networking Configuration — study guide chapter
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FAQ
Questions learners often ask
What does this LPIC-2 question test?
Advanced Networking Configuration — This question tests Advanced Networking Configuration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Check iptables rules for any OUTPUT chain that might be dropping packets. — Option D is correct because if the affected server can reach the remote server via other hosts on the same subnet, the issue is likely local to the affected server itself. Checking iptables rules on the OUTPUT chain can reveal whether a firewall rule is specifically dropping outbound packets destined for 192.168.1.50, which would not affect other hosts on the same subnet. This is a common cause of asymmetric connectivity problems where routing is otherwise properly configured.
What should I do if I get this LPIC-2 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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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