The answer is that this output indicates the TCP session is in the SYN_SENT state and not yet fully established. The `proto_state=01` value corresponds to a TCP session that has sent a SYN packet but has not yet received the corresponding SYN-ACK, meaning the three-way handshake is incomplete. This is a common trap on the Fortinet NSE 4 Network Security Professional exam, where candidates often confuse `proto_state=01` with an established session; in reality, an established TCP session shows `proto_state=02`. When you run `diagnose sys session filter dport 443` and see this output, the short `duration=3600` and `expire=3599` confirm it is a brand-new session still in the handshake phase. A useful memory tip is to think of state `01` as "one step in" — the first SYN has been sent, but the connection is not yet complete.
NSE4 Security Profiles Practice Question
This NSE4 practice question tests your understanding of security profiles. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 admin runs the following command on a FortiGate: 'diagnose sys session filter dport 443' and sees output: 'proto=6 proto_state=01 duration=3600 expire=3599'. 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 session is in the SYN_SENT state and is not yet fully established
Option D is correct. The session state '01' indicates a TCP session in the SYN_SENT state, meaning the session is still in the process of being established. The short duration and expire time suggest it is a new session.
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 stuck in a half-open state due to a firewall policy misconfiguration
Why it's wrong here
While possible, the state '01' is normal for a session in progress; it does not indicate a misconfiguration directly.
✓
The session is in the SYN_SENT state and is not yet fully established
Why this is correct
proto_state=01 corresponds to TCP SYN_SENT, meaning the three-way handshake is not complete.
Related concept
Read the scenario before looking for a memorised answer.
✗
The session is fully established and has been active for 3600 seconds
Why it's wrong here
A fully established TCP session would show state '05' (ESTABLISHED).
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Trap categories for this question
Command / output trap
A fully established TCP session would show state '05' (ESTABLISHED).
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 NSE4 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Security Profiles — This question tests Security Profiles — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The session is in the SYN_SENT state and is not yet fully established — Option D is correct. The session state '01' indicates a TCP session in the SYN_SENT state, meaning the session is still in the process of being established. The short duration and expire time suggest it is a new session.
What should I do if I get this NSE4 question wrong?
Identify which NSE4 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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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