- A
The session is a TCP connection that has been active for 1 hour and will expire in 3599 seconds
Why wrong: The session duration is 3600 seconds, not 1 hour? Actually 3600 seconds = 1 hour, so it has been active for 1 hour and has 3599 seconds left, meaning it will expire in about 1 hour more? Wait, expire is remaining lifetime. So total? This is confusing. Actually, the session is relatively old (1 hour) and has almost the same remaining time, which suggests a long timeout. This is typical. But the option says 'active for 1 hour and will expire in 3599 seconds' which is true, but not the best answer.
- B
The session is using TCP and has been open for 3600 seconds with a remaining lifetime of 3599 seconds, indicating it is a long-lived session
The output shows duration 3600 (seconds since session created) and expire 3599 (seconds until session removal). This is normal for a persistent HTTPS session.
- C
The session is UDP (proto=6 is TCP? Actually proto=6 is TCP) and the output indicates an ICMP error
Why wrong: Proto=6 is TCP, not UDP. Also no indication of ICMP.
- D
There is a problem because the session duration equals the expire time, meaning it will be removed immediately
Why wrong: Duration and expire are different; duration is already elapsed, expire is remaining. No immediate removal.
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 the following CLI command on a FortiGate: 'diagnose sys session filter dport 443' and see this output: proto=6 proto_state=01 duration=3600 expire=3599 What does this indicate?
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 using TCP and has been open for 3600 seconds with a remaining lifetime of 3599 seconds, indicating it is a long-lived session
Option B is correct because the output shows a TCP session (proto=6) with a duration of 3600 seconds (1 hour) and an expire value of 3599 seconds, meaning the session has been active for 3600 seconds and will be removed in 3599 seconds if no further traffic is seen. This indicates a long-lived session, typical for persistent connections like HTTPS, where the session timer resets with each packet.
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 is a TCP connection that has been active for 1 hour and will expire in 3599 seconds
Why it's wrong here
The session duration is 3600 seconds, not 1 hour? Actually 3600 seconds = 1 hour, so it has been active for 1 hour and has 3599 seconds left, meaning it will expire in about 1 hour more? Wait, expire is remaining lifetime. So total? This is confusing. Actually, the session is relatively old (1 hour) and has almost the same remaining time, which suggests a long timeout. This is typical. But the option says 'active for 1 hour and will expire in 3599 seconds' which is true, but not the best answer.
- ✓
The session is using TCP and has been open for 3600 seconds with a remaining lifetime of 3599 seconds, indicating it is a long-lived session
Why this is correct
The output shows duration 3600 (seconds since session created) and expire 3599 (seconds until session removal). This is normal for a persistent HTTPS session.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The session is UDP (proto=6 is TCP? Actually proto=6 is TCP) and the output indicates an ICMP error
- ✗
There is a problem because the session duration equals the expire time, meaning it will be removed immediately
Why it's wrong here
Duration and expire are different; duration is already elapsed, expire is remaining. No immediate removal.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates misinterpret 'duration' and 'expire' as being equal or see the large numbers and assume a problem, when in fact the values indicate a normal long-lived session with the TCP timeout nearly reached but not expired.
Trap categories for this question
Similar concept trap
The session duration is 3600 seconds, not 1 hour? Actually 3600 seconds = 1 hour, so it has been active for 1 hour and has 3599 seconds left, meaning it will expire in about 1 hour more? Wait, expire is remaining lifetime. So total? This is confusing. Actually, the session is relatively old (1 hour) and has almost the same remaining time, which suggests a long timeout. This is typical. But the option says 'active for 1 hour and will expire in 3599 seconds' which is true, but not the best answer.
Detailed technical explanation
How to think about this question
The 'diagnose sys session filter dport 443' command filters sessions by destination port 443 (HTTPS). The 'proto=6' indicates TCP (protocol number 6), and 'proto_state=01' corresponds to the TCP state 'ESTABLISHED' (as per RFC 793). The 'duration' field shows the session's age in seconds since creation, while 'expire' shows the remaining time before the session times out due to inactivity; the default TCP session timeout on FortiGate is 3600 seconds, so a session with duration 3600 and expire 3599 has been idle for almost the entire timeout period, yet it remains active—this is typical for keep-alive connections or long-lived HTTPS streams.
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.
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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 using TCP and has been open for 3600 seconds with a remaining lifetime of 3599 seconds, indicating it is a long-lived session — Option B is correct because the output shows a TCP session (proto=6) with a duration of 3600 seconds (1 hour) and an expire value of 3599 seconds, meaning the session has been active for 3600 seconds and will be removed in 3599 seconds if no further traffic is seen. This indicates a long-lived session, typical for persistent connections like HTTPS, where the session timer resets with each packet.
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
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Last reviewed: Jun 24, 2026
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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