The answer is DNS Filter with botnet C2 domain blocking because it proactively prevents the initial DNS resolution of the botnet's command-and-control domain, stopping the TLS handshake before it even begins. Since the traffic is encrypted with TLS, other security mechanisms like application control or IPS would require decryption to inspect the payload, which may not be feasible or configured. DNS Filter operates at Layer 7 without needing to decrypt the traffic, directly blocking the domain lookup based on FortiGuard's real-time threat intelligence. On the Fortinet NSE 7 Advanced Security NSE7 exam, this question tests your understanding of how to block botnet C2 encrypted traffic without relying on decryption policies—a common trap is choosing IPS or application control, which fail against encrypted flows. Remember the memory tip: "DNS first, C2 worst"—if you block the domain lookup, the encrypted handshake never starts.
NSE7 Advanced Threat Protection Practice Question
This NSE7 practice question tests your understanding of advanced threat protection. 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.
A FortiGate administrator receives alerts about a device communicating with a known botnet C2 server. The traffic is encrypted with TLS. Which ATP feature is most effective to block this communication?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
DNS Filter with botnet C2 domain blocking
DNS Filter with botnet C2 domain blocking is the most effective because it proactively prevents the initial DNS resolution of the botnet's command-and-control domain, stopping the TLS handshake before it even begins. Since the traffic is encrypted with TLS, other security mechanisms like application control or IPS would require decryption to inspect the payload, which may not be feasible or configured. DNS Filter operates at Layer 7 without needing to decrypt the traffic, directly blocking the domain lookup based on FortiGuard's real-time threat intelligence.
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.
✗
Application control to block the C2 application
Why it's wrong here
Application control may not identify the C2 traffic as a specific application.
✗
Antivirus profile with SSL inspection
Why it's wrong here
Antivirus can detect malware but not necessarily block C2 if the traffic is just a beacon.
✗
IPS signature for botnet activity
Why it's wrong here
IPS may detect but requires SSL inspection for encrypted traffic.
✓
DNS Filter with botnet C2 domain blocking
Why this is correct
DNS filter blocks resolution of known malicious domains, preventing communication.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume encrypted traffic requires SSL inspection to block it, but DNS Filter blocks the domain resolution before encryption occurs, making it the most efficient and non-intrusive solution for C2 communication.
Detailed technical explanation
How to think about this question
DNS Filter leverages FortiGuard's botnet domain database, which is updated in real-time via the FortiGuard Distribution Network (FDN). When a client attempts to resolve a known C2 domain, the FortiGate's DNS Filter intercepts the DNS query (typically UDP/53) and returns a blocked response (e.g., 0.0.0.0 or a FortiGuard sinkhole IP), preventing the client from ever obtaining the server's IP address. This technique is effective even against TLS-encrypted C2 traffic because it blocks the communication at the DNS resolution stage, before any encrypted session is established.
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.
Advanced Threat Protection — This question tests Advanced Threat Protection — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: DNS Filter with botnet C2 domain blocking — DNS Filter with botnet C2 domain blocking is the most effective because it proactively prevents the initial DNS resolution of the botnet's command-and-control domain, stopping the TLS handshake before it even begins. Since the traffic is encrypted with TLS, other security mechanisms like application control or IPS would require decryption to inspect the payload, which may not be feasible or configured. DNS Filter operates at Layer 7 without needing to decrypt the traffic, directly blocking the domain lookup based on FortiGuard's real-time threat intelligence.
What should I do if I get this NSE7 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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This NSE7 practice question is part of Courseiva's free Fortinet 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 NSE7 exam.
Question Discussion
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