200-201 Security Concepts Practice Question
A security analyst is examining a network capture and observes that an attacker is sending a large volume of SYN packets to a web server with spoofed source IP addresses. The server's connection table is filling up, and legitimate users cannot connect. Which type of attack is the analyst observing?
⚠ Common exam trap
The trap here is grouping all denial-of-service attacks together and overlooking that SYN floods specifically exhaust TCP connection state with spoofed half-open connections.
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
✓
A TCP SYN flood, which exhausts the server's connection table with half-open connections.
The capture shows many SYN packets with spoofed sources, and the server's connection table is exhausted, blocking legitimate users. This is the classic signature of a TCP SYN flood, a denial-of-service attack that abuses the TCP three-way handshake. Smurf uses ICMP, DNS amplification uses resolvers, and man-in-the-middle intercepts traffic, so none match the observed half-open connection exhaustion.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A DNS amplification attack, which uses open resolvers to send large responses to a victim.
Why it's wrong here
DNS amplification abuses open DNS resolvers to send large responses to a spoofed victim address, amplifying traffic volume. The scenario involves TCP SYN packets to a web server, not DNS queries or responses. While both are volumetric denial-of-service techniques, the specific mechanism of half-open TCP connections is characteristic of a SYN flood, not DNS amplification.
- ✗
A man-in-the-middle attack, which intercepts and relays traffic between two parties.
Why it's wrong here
A man-in-the-middle attack positions the attacker between two communicating parties to intercept or alter traffic. It does not inherently exhaust a server's connection table or prevent legitimate connections through SYN flooding. The scenario shows resource exhaustion from spoofed SYN packets, which is a denial-of-service condition, not an interception technique.
- ✗
A Smurf attack, which uses ICMP echo requests with a spoofed source to amplify traffic.
Why it's wrong here
A Smurf attack floods a victim with ICMP echo replies by sending echo requests to a broadcast address with the victim's spoofed source. The scenario describes TCP SYN packets filling a connection table, not ICMP traffic, so the observed behavior does not match Smurf. The analyst would see ICMP echo traffic and broadcast amplification, not half-open TCP connections.
- ✓
A TCP SYN flood, which exhausts the server's connection table with half-open connections.
Why this is correct
A TCP SYN flood sends many SYN packets with spoofed sources. The server allocates resources for each half-open connection and waits for the final ACK that never arrives, exhausting the connection table and denying service to legitimate users. This exactly matches the observed SYN volume, spoofed IPs, and full connection table, making it the correct classification.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 200-201 practice question is part of Courseiva's free Cisco 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 200-201 exam.