- A
Man-in-the-middle attack
Why wrong: A man-in-the-middle attack involves intercepting communications between two parties, not sending a flood of SYN packets.
- B
SYN flood attack
A SYN flood attack is characterized by sending numerous SYN packets without completing the handshake, overwhelming the victim's connection table. The internal server is likely compromised and acting as the attacker.
- C
DDoS amplification attack
Why wrong: Amplification attacks use small queries that generate large responses (e.g., NTP, DNS). Sending raw SYN packets is not an amplification technique.
- D
Smurf attack
Why wrong: A Smurf attack involves sending ICMP echo requests to a network broadcast address with a spoofed source IP, causing many replies to flood the victim. This scenario describes TCP SYN packets, not ICMP.
Quick Answer
The answer is a SYN flood attack, because the described behavior—an internal server sending a high volume of TCP SYN packets without completing the three-way handshake—is the classic signature of this denial-of-service technique. In a SYN flood, the attacker initiates half-open connections by sending SYN packets and never replying with the final ACK, which forces the target’s connection table to fill up and exhaust server resources. On the CompTIA Network+ N10-009 exam, this scenario often appears as a trick: the question may describe the traffic originating from an internal server, but the key is that the handshake is never finished, not the direction of the packets. A common trap is confusing this with a SYN scan or a normal TCP connection attempt, but remember that a flood involves volume and incompletion, not just probing. Memory tip: “SYN sent, ACK absent—resources spent.”
N10-009 Network Security Practice Question
This N10-009 practice question tests your understanding of network security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 security analyst observes that an internal server is sending a large volume of TCP SYN packets to various external IP addresses, but never completing the three-way handshake. This behavior is indicative of which type of attack?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"never"Why it matters: Absolute qualifier. True only if the statement has zero exceptions — be cautious of options that seem obvious but break down in edge cases.
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
SYN flood attack
The correct answer is B. A SYN flood attack occurs when an attacker sends a high volume of TCP SYN packets to a target but never completes the three-way handshake by sending the final ACK. This leaves the target's connection table half-open, consuming resources and potentially exhausting its ability to accept legitimate connections. The observed behavior—internal server sending many SYN packets without completing the handshake—matches the classic signature of a SYN flood, though typically the attacker spoofs the source IP to avoid response traffic.
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.
- ✗
Man-in-the-middle attack
Why it's wrong here
A man-in-the-middle attack involves intercepting communications between two parties, not sending a flood of SYN packets.
- ✓
SYN flood attack
Why this is correct
A SYN flood attack is characterized by sending numerous SYN packets without completing the handshake, overwhelming the victim's connection table. The internal server is likely compromised and acting as the attacker.
Clue confirmation
The clue word "never" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
DDoS amplification attack
- ✗
Smurf attack
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA often tests the distinction between a SYN flood (which uses TCP SYN packets and incomplete handshakes) and a DDoS amplification attack (which uses UDP or other protocols with spoofed sources), so candidates mistakenly choose amplification when they see 'large volume' and 'external IPs' without recognizing the TCP SYN signature.
Trap categories for this question
Scenario analysis trap
A Smurf attack involves sending ICMP echo requests to a network broadcast address with a spoofed source IP, causing many replies to flood the victim. This scenario describes TCP SYN packets, not ICMP.
Detailed technical explanation
How to think about this question
Under the hood, a SYN flood exploits the TCP three-way handshake: the server allocates memory in a Transmission Control Block (TCB) upon receiving a SYN and sends a SYN-ACK, then waits for the final ACK. With a backlog queue (e.g., net.core.somaxconn default 128 or 4096), the server can only hold a limited number of half-open connections. Attackers often spoof the source IP to prevent the server from receiving RST packets from non-existent hosts, and modern defenses include SYN cookies (RFC 4987) that encode connection state in the SYN-ACK sequence number, avoiding resource allocation until the handshake completes.
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 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
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this N10-009 question test?
Network Security — This question tests Network Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: SYN flood attack — The correct answer is B. A SYN flood attack occurs when an attacker sends a high volume of TCP SYN packets to a target but never completes the three-way handshake by sending the final ACK. This leaves the target's connection table half-open, consuming resources and potentially exhausting its ability to accept legitimate connections. The observed behavior—internal server sending many SYN packets without completing the handshake—matches the classic signature of a SYN flood, though typically the attacker spoofs the source IP to avoid response traffic.
What should I do if I get this N10-009 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "never". Absolute qualifier. True only if the statement has zero exceptions — be cautious of options that seem obvious but break down in edge cases.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This N10-009 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 N10-009 exam.
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