This LPIC-1 practice question tests your understanding of essential system services and networking. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 sysadmin notices that after modifying iptables rules, the SSH service is unreachable from a specific subnet (192.168.1.0/24). Which command should be used to view the current rules with line numbers for easier identification?
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.
iptables -L
Why wrong: Shows rules but without line numbers.
iptables -L --line-numbers
Shows rules with line numbers for easier editing.
iptables -t raw -L
Why wrong: Shows raw table, not relevant for SSH filtering.
iptables -t nat -L
Why wrong: Shows NAT table, not filter table for SSH.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
iptables -L --line-numbers
Option B is correct because iptables -L --line-numbers displays rules with line numbers, helpful for inserting or deleting rules. Option A is wrong because it shows rules but without line numbers. Option C is wrong because it shows the NAT table, not the filter table affecting SSH. Option D is wrong because it shows raw table.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
iptables -L
Why it's wrong here
Shows rules but without line numbers.
iptables -L --line-numbers
Why this is correct
Shows rules with line numbers for easier editing.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
CIDR notation defines the prefix length.
iptables -t raw -L
Why it's wrong here
Shows raw table, not relevant for SSH filtering.
iptables -t nat -L
Common exam traps
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Trap categories for this question
Command / output trap
Shows rules but without line numbers.
Detailed technical explanation
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related LPIC-1 subnetting questions on CIDR, address ranges, and subnet selection.
Essential System Services and Networking — study guide chapter
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FAQ
Essential System Services and Networking — This question tests Essential System Services and Networking — CIDR notation defines the prefix length..
The correct answer is: iptables -L --line-numbers — Option B is correct because iptables -L --line-numbers displays rules with line numbers, helpful for inserting or deleting rules. Option A is wrong because it shows rules but without line numbers. Option C is wrong because it shows the NAT table, not the filter table affecting SSH. Option D is wrong because it shows raw table.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related LPIC-1 subnetting questions on CIDR, address ranges, and subnet selection.
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.
CIDR notation defines the prefix length.
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Last reviewed: Jun 24, 2026
This LPIC-1 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-1 exam.
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