This NSE4 practice question tests your understanding of firewall policies and nat. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 admin runs 'diagnose sys session filter src 10.0.0.10' and gets no output. What does this indicate?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The source IP 10.0.0.10 is not currently active in any session table
The 'diagnose sys session filter' command in FortiGate is used to filter and display active session entries in the session table. When the command 'diagnose sys session filter src 10.0.0.10' returns no output, it means that no session in the session table matches the source IP address 10.0.0.10, indicating that this IP is not currently involved in any active session. This does not imply the session table is full, a policy block, or a syntax error.
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 session table is full
Why it's wrong here
If the table is full, there would be many sessions; the filter would still show any matching.
✓
The source IP 10.0.0.10 is not currently active in any session table
Why this is correct
No sessions match the filter; the source is either idle or the session expired.
Related concept
Read the scenario before looking for a memorised answer.
✗
The firewall policy is blocking traffic from 10.0.0.10
Why it's wrong here
Blocked traffic does not create sessions; the command would still show no output.
✗
The diagnose command syntax is incorrect
Why it's wrong here
The syntax is correct; no output is valid.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may assume no output means a syntax error or a full session table, but FortiGate clearly indicates syntax errors with an error message, and a full table still shows existing sessions; the correct interpretation is that the source IP has no active sessions.
Trap categories for this question
Command / output trap
If the table is full, there would be many sessions; the filter would still show any matching.
Detailed technical explanation
How to think about this question
The FortiGate session table stores stateful session entries for all active connections, including TCP, UDP, and ICMP. The 'diagnose sys session filter' command applies a filter before displaying sessions; if no session matches, the output is empty. This is useful for troubleshooting connectivity issues, as it confirms that no traffic from that source has been processed by the firewall, which could be due to policy denial, routing issues, or simply no traffic.
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 practitioner preparing for the NSE4 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
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.
Firewall Policies and NAT — This question tests Firewall Policies and NAT — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The source IP 10.0.0.10 is not currently active in any session table — The 'diagnose sys session filter' command in FortiGate is used to filter and display active session entries in the session table. When the command 'diagnose sys session filter src 10.0.0.10' returns no output, it means that no session in the session table matches the source IP address 10.0.0.10, indicating that this IP is not currently involved in any active session. This does not imply the session table is full, a policy block, or a syntax error.
What should I do if I get this NSE4 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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Question Discussion
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