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?
The session is blocked by a firewall policy
Why wrong: A session entry indicates it is allowed.
The session is a UDP connection to port 443
Why wrong: Proto=6 is TCP, not UDP.
The session is experiencing high latency
Why wrong: The output does not show latency.
The session is a TCP connection to port 443 that has been active for 1 hour
Duration 3600 seconds = 1 hour. Proto=6 is TCP.
Answer choices
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 connection to port 443 that has been active for 1 hour
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.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The session is blocked by a firewall policy
Why it's wrong here
A session entry indicates it is allowed.
The session is a UDP connection to port 443
The session is experiencing high latency
Why it's wrong here
The output does not show latency.
The session is a TCP connection to port 443 that has been active for 1 hour
Why this is correct
Duration 3600 seconds = 1 hour. Proto=6 is TCP.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates often confuse `proto=6` with UDP or misinterpret `duration` as a latency value, leading them to select the high-latency or UDP options instead of recognizing the TCP protocol number and session age.
Trap categories for this question
Command / output trap
The output does not show latency.
Detailed technical explanation
In FortiOS, `diagnose sys session filter` is used to filter and display session table entries. The `proto=6` corresponds to TCP per IANA protocol numbers, and `proto_state=01` typically represents a TCP session in the ESTABLISHED state (TCP state machine value 1). The `duration` field counts seconds since the session was created, while `expire` shows the remaining time before the session times out (default TCP session timeout is often 3600 seconds). Understanding these fields is critical for troubleshooting long-lived connections like HTTPS or database replication.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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.
What to study next
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FAQ
System and Network Administration — This question tests System and Network Administration — Read the scenario before looking for a memorised answer..
The correct answer is: The session is a TCP connection to port 443 that has been active for 1 hour — 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.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
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