The correct answer is that the host is participating in an NTP amplification DDoS attack. This is because the attacker has compromised or misconfigured the internal Linux server to send small NTP queries with a spoofed source IP—the victim’s address—to numerous open NTP servers, which then flood the victim with large responses, amplifying the traffic. In this scenario, the internal host acts as the reflector, generating the outbound UDP spike on port 123 to diverse external IPs, while the lack of IDS alerts indicates the traffic mimics legitimate NTP queries. On the Cisco CyberOps Associate 200-201 exam, this question tests your ability to distinguish between a host being the victim versus the amplifier in a reflection attack; a common trap is assuming the internal host is the target when the outbound traffic pattern reveals it is the source of the queries. To detect NTP amplification DDoS attacks, remember that small queries in, big responses out—think of it as a “tiny ask, massive reply” principle, and always check which IP is spoofed to identify the true victim.
200-201 Network Intrusion Analysis Practice Question
This 200-201 practice question tests your understanding of network intrusion analysis. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
You are monitoring network traffic and notice a sudden spike in outbound UDP traffic from a single internal host to various external IPs on port 123 (NTP). The traffic pattern shows a high volume of small packets. The host in question is a Linux server that does not run any NTP services. The IDS does not generate any alerts for this traffic. Which type of attack is most likely occurring?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The host is participating in an NTP amplification DDoS attack.
The sudden spike in outbound UDP traffic from a single internal host to multiple external IPs on port 123 (NTP) with small packets indicates the host is being used as a reflector in an NTP amplification DDoS attack. The attacker spoofs the victim's IP address and sends small queries to open NTP servers, which respond with large replies directed at the victim, but in this scenario the internal host is the one sending the queries (likely due to malware or misconfiguration), making it the amplifier. The lack of IDS alerts suggests the traffic matches normal NTP patterns, but the volume and destination diversity confirm the attack.
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.
✓
The host is participating in an NTP amplification DDoS attack.
Why this is correct
NTP amplification uses small queries to generate large responses; the outbound traffic is the queries.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The host is scanning for open NTP servers.
Why it's wrong here
Scanning would show traffic to multiple ports, not just to port 123 on many IPs.
✗
Data exfiltration via NTP tunneling.
Why it's wrong here
NTP tunneling is possible but less common; the volume and pattern suggest amplification.
✗
The host is performing an NTP time synchronization query.
Why it's wrong here
The host does not run NTP services and the volume is too high for normal sync.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between being a victim of amplification (receiving large responses) versus being the amplifier (sending queries), and candidates mistakenly assume the host is the victim when the outbound traffic indicates it is the source of the queries.
Trap categories for this question
Command / output trap
Scanning would show traffic to multiple ports, not just to port 123 on many IPs.
Detailed technical explanation
How to think about this question
NTP amplification exploits the monlist command (deprecated in NTPv4 but still supported in older implementations) or other commands that allow a small query to generate a large response (up to 100x amplification factor). In this attack, the internal host's IP is likely spoofed by the attacker, but the observed outbound traffic indicates the host itself is compromised and sending the queries, acting as a reflector; the IDS may not alert because the packets conform to legitimate NTP protocol structure, but the volume and destination diversity are red flags. Real-world scenarios often involve IoT devices or misconfigured servers being recruited into botnets for DDoS campaigns.
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.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Network Intrusion Analysis — This question tests Network Intrusion Analysis — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The host is participating in an NTP amplification DDoS attack. — The sudden spike in outbound UDP traffic from a single internal host to multiple external IPs on port 123 (NTP) with small packets indicates the host is being used as a reflector in an NTP amplification DDoS attack. The attacker spoofs the victim's IP address and sends small queries to open NTP servers, which respond with large replies directed at the victim, but in this scenario the internal host is the one sending the queries (likely due to malware or misconfiguration), making it the amplifier. The lack of IDS alerts suggests the traffic matches normal NTP patterns, but the volume and destination diversity confirm the attack.
What should I do if I get this 200-201 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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