The correct answer is that the session is in a TCP SYN-SENT state and has not completed the three-way handshake. This is determined by the `proto_state=01` value in the `diagnose sys session filter dport 443` output, where `proto=6` confirms TCP and state 01 specifically maps to the SYN-SENT phase in FortiGate’s session table. The `duration=3600` and `expire=3599` fields reveal the session has existed for an hour but will expire in just under an hour because the handshake was never finalized, leaving it in a half-open state. On the Fortinet NSE 7 Advanced Security NSE7 exam, this command tests your ability to interpret real-time session diagnostics and distinguish between established and incomplete TCP connections—a common trap is confusing `proto_state=01` with an established state like ESTABLISHED (state 02). Remember the memory tip: “State 01 is the one that’s just begun; no handshake done, it will soon be gone.”
NSE7 Enterprise Firewall and VDOMs Practice Question
This NSE7 practice question tests your understanding of enterprise firewall and vdoms. 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.
An administrator 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 about the session?
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 a TCP SYN-SENT state and has not completed the three-way handshake
The output shows 'proto=6' (TCP) and 'proto_state=01', which in FortiGate's session table corresponds to TCP state SYN-SENT (the first step of the three-way handshake). The 'duration=3600' indicates the session has existed for 3600 seconds, but 'expire=3599' shows it will expire in 3599 seconds because the handshake was never completed. This confirms the session is not fully established, making option C correct.
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 fully established and has been active for 1 hour
Why it's wrong here
proto_state=01 is SYN-SENT, not established. Established would show a different state.
✗
The session will expire in 3600 seconds and has been active for 3599 seconds
Why it's wrong here
The values are swapped: duration=3600, expire=3599.
✓
The session is in a TCP SYN-SENT state and has not completed the three-way handshake
Why this is correct
proto_state=01 corresponds to TCP SYN-SENT (the first packet). The handshake is incomplete.
Related concept
Read the scenario before looking for a memorised answer.
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse the 'duration' and 'expire' values or assume 'proto=6' and a long duration imply an established session, but FortiGate's 'proto_state' field is the key to identifying the TCP handshake phase.
Trap categories for this question
Command / output trap
proto_state=01 is SYN-SENT, not established. Established would show a different state.
Detailed technical explanation
How to think about this question
FortiGate uses internal state codes for TCP sessions: 'proto_state=01' maps to TCP_SYN_SENT (the client has sent a SYN but not received a SYN-ACK), while 'proto_state=02' is TCP_ESTABLISHED. The session timeout for an incomplete handshake is typically 10 seconds by default, but the output shows a 3600-second duration because the session was created 3600 seconds ago and is still in SYN-SENT, likely due to a firewall policy or asymmetric routing preventing the SYN-ACK from returning. In real-world scenarios, this can indicate a misconfigured load balancer or a DDoS SYN flood attempt.
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 NSE7 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.
Enterprise Firewall and VDOMs — This question tests Enterprise Firewall and VDOMs — 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 a TCP SYN-SENT state and has not completed the three-way handshake — The output shows 'proto=6' (TCP) and 'proto_state=01', which in FortiGate's session table corresponds to TCP state SYN-SENT (the first step of the three-way handshake). The 'duration=3600' indicates the session has existed for 3600 seconds, but 'expire=3599' shows it will expire in 3599 seconds because the handshake was never completed. This confirms the session is not fully established, making option C correct.
What should I do if I get this NSE7 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 →
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. An administrator runs the command 'diagnose sys session filter dport 443' on a FortiGate and sees the following output:
proto=6 proto_state=01 duration=3600 expire=3599
What does this indicate about the session?
hard
✓ A.The session is in SYN_SENT state, meaning the three-way handshake is incomplete
B.The session is fully established and will expire in about 3599 seconds
C.The traffic is being blocked by the firewall policy
D.The session is using HTTPS and has been inspected
Why A: The output shows `proto=6` (TCP), `proto_state=01`, `duration=3600`, and `expire=3599`. In FortiGate's session table, `proto_state=01` represents the TCP state `SYN_SENT`, which means the session has sent a SYN but has not yet received a SYN-ACK, so the three-way handshake is incomplete. The `expire=3599` indicates the session will time out in 3599 seconds if the handshake does not complete, but the session is not yet established.
Variation 2. A FortiGate administrator runs the following command and sees the output:
diagnose sys session filter dport 443
diagnose sys session list
Output shows sessions with proto=6 and expire time decreasing. What does this indicate?
medium
A.The sessions are using UDP protocol
B.The FortiGate is performing deep packet inspection on these sessions
C.The sessions are being blocked by a firewall policy
✓ D.The sessions are TCP sessions and are active
Why D: The command 'diagnose sys session filter dport 443' filters sessions with destination port 443, and 'diagnose sys session list' displays them. The output shows 'proto=6', which is the protocol number for TCP (per IANA protocol numbers). The 'expire time decreasing' indicates that the session timer is counting down, which is normal behavior for an active TCP session that is being refreshed by ongoing traffic. Therefore, the sessions are TCP and active.
Last reviewed: Jun 24, 2026
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