Quick Answer
The answer is tcpdump, traceroute, and ping. Tcpdump is correct because it captures and analyzes network packets in real time, allowing you to inspect traffic at the interface level to diagnose issues like packet loss, retransmissions, or suspicious activity. Traceroute uses ICMP (or UDP on some systems) to trace the path packets take to a destination, revealing each hop’s IP address and round-trip time, which helps identify routing issues or latency bottlenecks. On the Linux Foundation Certified System Administrator LFCS exam, these tools test your ability to perform practical network diagnostics from the command line—expect scenario-based questions where you must choose the right tool for a given symptom, such as using ping to verify basic connectivity or tcpdump to isolate a protocol error. A common trap is confusing traceroute with tracepath; remember that traceroute gives more granular control over options like port and TTL. For a quick memory tip, think “Ping to check, Traceroute to trace, Tcpdump to inspect the face.”
This LFCS practice question tests your understanding of networking. 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 THREE are common tools used for network troubleshooting on Linux?
traceroute
Traces the route packets take to a destination.
fdisk
Why wrong: Used for disk partition management, not networking.
ping
Used to test reachability and measure round-trip time.
tcpdump
Captures and analyzes network packets.
useradd
Why wrong: Used to create user accounts.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
traceroute
A. traceroute is correct because it uses ICMP (or UDP on some systems) to trace the path packets take to a destination, revealing each hop's IP address and round-trip time. This helps identify routing issues, packet loss, or latency bottlenecks in the network path.
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.
traceroute
Why this is correct
Traces the route packets take to a destination.
Related concept
Read the scenario before looking for a memorised answer.
fdisk
Why it's wrong here
Used for disk partition management, not networking.
ping
Why this is correct
Used to test reachability and measure round-trip time.
Related concept
Read the scenario before looking for a memorised answer.
tcpdump
Why this is correct
Captures and analyzes network packets.
Related concept
Read the scenario before looking for a memorised answer.
useradd
Why it's wrong here
Used to create user accounts.
Common exam traps
The trap here is that candidates might confuse system administration tools (like fdisk and useradd) with network utilities, or incorrectly assume that any command that interacts with the system can be used for network troubleshooting, when only dedicated network diagnostic tools like traceroute, ping, and tcpdump are appropriate.
Detailed technical explanation
traceroute works by sending packets with incrementing TTL (Time To Live) values, starting at 1; each router along the path decrements the TTL and, when it reaches 0, sends back an ICMP Time Exceeded message, revealing the router's IP. In real-world scenarios, traceroute can differentiate between ICMP filtering (where hops may not respond) and actual routing loops, and it's often used alongside mtr for continuous path analysis.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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
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FAQ
Networking — This question tests Networking — Read the scenario before looking for a memorised answer..
The correct answer is: traceroute — A. traceroute is correct because it uses ICMP (or UDP on some systems) to trace the path packets take to a destination, revealing each hop's IP address and round-trip time. This helps identify routing issues, packet loss, or latency bottlenecks in the network path.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 2026
This LFCS practice question is part of Courseiva's free Linux Foundation 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 LFCS exam.
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