CS0-003 Security Operations Practice Question
An analyst needs to capture network traffic on a Linux server to investigate a potential data exfiltration. Which command-line tool is best suited for real-time packet capture and analysis?
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
✓
tcpdump
tcpdump is a powerful command-line packet analyzer for Linux, capable of capturing network traffic in real time and saving it for later analysis.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
tcpdump
Why this is correct
tcpdump is the industry-standard command-line utility for capturing and analyzing network packets directly on Linux systems. It interfaces with the libpcap library to intercept and display TCP/IP and other packets being transmitted or received over a network interface. Analysts can apply complex Berkeley Packet Filter (BPF) expressions to isolate specific traffic of interest for real-time analysis or save the capture to a PCAP file for offline inspection.
- ✗
netstat
Why it's wrong here
netstat (network statistics) is a command-line tool used to display active network connections, routing tables, interface statistics, masquerade connections, and multicast memberships. While it is invaluable for identifying open ports, listening sockets, and established connections on a host, it lacks the capability to capture, inspect, or log individual raw network packets.
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iperf
Why it's wrong here
iperf is a standardized network testing tool used to measure maximum achievable bandwidth on IP networks. It works by generating active traffic streams (TCP, UDP, or SCTP) between a client and a server to test throughput, loss, and jitter. Because it is designed solely for performance benchmarking and active traffic generation, it cannot intercept or record ambient network traffic.
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nmap
Why it's wrong here
nmap (Network Mapper) is an open-source utility designed for network discovery, port scanning, and vulnerability assessment. It operates by sending custom-crafted packets to target hosts and analyzing the responses to determine active hosts, open ports, and operating system versions. It is an active scanning tool rather than a passive packet capture utility, making it unsuitable for monitoring or recording ongoing network traffic.
Go deeper
Related to this question
Learn chapter
NetFlow and Traffic Flow Analysis
Key term
Analysis
In incident response, analysis is the process of examining data and events to determine what happened, how it happened, and what actions to take.
Key term
Packet capture
Packet capture is the process of intercepting and recording data packets traveling over a computer network for analysis.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CS0-004 practice question is part of Courseiva's free CompTIA 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 CS0-004 exam.