Question 1hardmultiple choice
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Quick Answer
The correct answer is that this indicates a TCP session to port 443 that has been active for 3600 seconds and will expire in 3599 seconds. This is because the `proto=6` field corresponds to the protocol number for TCP, while `dport=443` confirms the destination is HTTPS traffic; the `duration=3600` and `expire=3599` values directly show the session’s age and remaining lifetime in seconds. On the Fortinet NSE 4 Network Security Professional exam, you must be able to interpret `diagnose sys session filter` output quickly, as it tests your ability to read session state fields like `proto_state=01`, which is a TCP state code, and to distinguish between duration and expiry. A common trap is confusing `expire` with total timeout—remember that `expire` counts down, not up. For a quick memory tip, think of `proto=6` as “TCP on port 6” (though it’s actually protocol 6), and pair `duration` with “how long it’s been alive” versus `expire` with “how long until it dies.”
NSE4 System and Network Administration Practice Question
This NSE4 practice question tests your understanding of system and network administration. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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 run 'diagnose sys session filter dport 443' and see the following output: proto=6 proto_state=01 duration=3600 expire=3599 What does this indicate about the session?
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
✓
The session is a TCP session to port 443 that has been active for 3600 seconds and will expire in 3599 seconds.
Option C is correct because the output shows 'proto=6', which is the protocol number for TCP, and 'dport=443' indicates the destination port is HTTPS. The 'duration=3600' means the session has been active for 3600 seconds, and 'expire=3599' means it will expire in 3599 seconds. The 'proto_state=01' is a TCP state code, confirming this is a TCP session.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse protocol numbers (e.g., thinking '6' is UDP or ICMP) or misinterpret 'expire' as the time since expiration rather than the remaining time until expiration.
Detailed technical explanation
How to think about this question
In Fortinet's FortiOS, the 'diagnose sys session filter' command filters session table entries, and 'proto=6' corresponds to TCP as defined by IANA protocol numbers. The 'proto_state=01' for TCP typically indicates a session in the 'established' state (SYN_SENT or ESTABLISHED depending on the implementation). The 'expire' value is a countdown timer; when it reaches 0, the session is removed. This is critical for troubleshooting firewall performance and session timeouts in high-traffic environments.
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.
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FAQ
Questions learners often ask
What does this NSE4 question test?
System and Network Administration — This question tests System and Network Administration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The session is a TCP session to port 443 that has been active for 3600 seconds and will expire in 3599 seconds. — Option C is correct because the output shows 'proto=6', which is the protocol number for TCP, and 'dport=443' indicates the destination port is HTTPS. The 'duration=3600' means the session has been active for 3600 seconds, and 'expire=3599' means it will expire in 3599 seconds. The 'proto_state=01' is a TCP state code, confirming this is a TCP session.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
2 more ways this is tested on NSE4
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. You run 'diagnose sys session filter dport 443' and see the following output: proto=6 proto_state=01 duration=3600 expire=3599 What does this indicate?
easy- A.The session is in a half-closed state
- B.The session is about to expire
- C.The session is a UDP session
- ✓ D.The session is active and established
Why D: The output shows `proto=6` (TCP), `proto_state=01` (TCP ESTABLISHED), `duration=3600` seconds, and `expire=3599` seconds remaining. This indicates a fully established TCP session that has been active for one hour and still has nearly a full hour of idle timeout remaining. Therefore, the session is active and established, making option D correct.
Variation 2. You run 'diagnose sys session filter dport 443' and see the following output: proto=6 proto_state=01 duration=3600 expire=3599 What does this indicate?
medium- A.The session is blocked by a firewall policy
- B.The session is a UDP connection to port 443
- C.The session is experiencing high latency
- ✓ D.The session is a TCP connection to port 443 that has been active for 1 hour
Why D: Option D is correct because the output shows `proto=6`, which is the protocol number for TCP, and `dport=443` indicates the destination port is HTTPS. The `duration=3600` field means the session has been active for 3600 seconds (1 hour), and `expire=3599` shows the remaining lifetime in seconds. This confirms an active TCP session to port 443 that has been established for one hour.
Last reviewed: Jun 24, 2026
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