The answer is that the signature’s action is set to ‘monitor’ in the IPS sensor, overriding the block action configured in the IPS profile. This happens because Fortinet’s IPS architecture applies a two-layer hierarchy: the IPS sensor defines the default action for each signature, and the IPS profile in the firewall policy can only tighten or loosen that action—but it cannot override a sensor-level ‘monitor’ or ‘pass’ setting to enforce a block. On the NSE 4 exam, this scenario tests your understanding of how IPS sensor and profile actions interact, often appearing as a trick where candidates assume the profile’s block action is absolute. A common trap is forgetting that the sensor’s action takes precedence; if the sensor says ‘monitor,’ the profile’s block is ignored, and traffic is only logged. Memory tip: think “sensor sets the floor, profile builds the walls—but if the floor is ‘monitor,’ you can’t build a block wall.”
NSE4 Security Profiles Practice Question
This NSE4 practice question tests your understanding of security profiles. 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.
An administrator configures an IPS profile with a signature that has a 'block' action. However, traffic matching the signature is only being logged and not blocked. What is the most likely reason?
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 signature's action is set to 'monitor' in the IPS sensor
IPS signatures can be set to 'block' but the actual action in the firewall policy's IPS profile may be overridden by the policy's inspection mode or the IPS profile's configuration. Additionally, the signature's action must not be set to 'monitor' or 'pass' at the sensor level.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 IPS profile is applied to the inbound policy only
Why it's wrong here
The direction does not change the action from block to monitor.
✗
The firewall policy is set to 'accept' but logging is disabled
Why it's wrong here
The policy action affects whether traffic is allowed; logging is separate.
✗
The FortiGate is operating in flow-based inspection mode
Why it's wrong here
Flow-based inspection still applies IPS actions; it does not downgrade block to monitor.
✓
The signature's action is set to 'monitor' in the IPS sensor
Why this is correct
If the signature is configured to 'monitor' in the IPS sensor, it will only log, regardless of the default action.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related NSE4 NAT questions on configuration and troubleshooting.
Security Profiles — This question tests Security Profiles — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The signature's action is set to 'monitor' in the IPS sensor — IPS signatures can be set to 'block' but the actual action in the firewall policy's IPS profile may be overridden by the policy's inspection mode or the IPS profile's configuration. Additionally, the signature's action must not be set to 'monitor' or 'pass' at the sensor level.
What should I do if I get this NSE4 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related NSE4 NAT questions on configuration and troubleshooting.
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?
Static NAT maps one inside address to one outside address.
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This NSE4 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 NSE4 exam.
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