Exam F5CAB4 Topic 8 Question 2 Discussion
Actual exam question for F5's F5CAB4 exam
Question #: 2
Topic #: 8
Question #: 2
Topic #: 8
The BIG-IP Administrator runs the command:
netstat -an | grep 443
and sees the following output:
tcp 0 0 0.0.0.0:443 0.0.0.0:* LISTEN
What does this output indicate about the service on port 443? (Choose one answer)
netstat -an | grep 443
and sees the following output:
tcp 0 0 0.0.0.0:443 0.0.0.0:* LISTEN
What does this output indicate about the service on port 443? (Choose one answer)
Suggested Answer: B Vote an answer
Comprehensive and Detailed Explanation From BIG-IP Administration Control Plane Administration documents:
In netstat output:
0.0.0.0:443 means the service is bound to all available IPv4 interfaces on the system.
LISTEN indicates the service is actively waiting for incoming connection requests.
Therefore, this output confirms that a service (commonly HTTPS/443, such as the BIG-IP Configuration Utility or an application listener) is actively listening on all interfaces, making B the correct answer.
Why the other options are incorrect:
A would show 127.0.0.1:443 if it were loopback-only.
C is incorrect because LISTEN explicitly indicates readiness to accept connections.
D is unrelated; standby state does not affect socket binding shown by netstat.
Hence, the correct answer is B.
In netstat output:
0.0.0.0:443 means the service is bound to all available IPv4 interfaces on the system.
LISTEN indicates the service is actively waiting for incoming connection requests.
Therefore, this output confirms that a service (commonly HTTPS/443, such as the BIG-IP Configuration Utility or an application listener) is actively listening on all interfaces, making B the correct answer.
Why the other options are incorrect:
A would show 127.0.0.1:443 if it were loopback-only.
C is incorrect because LISTEN explicitly indicates readiness to accept connections.
D is unrelated; standby state does not affect socket binding shown by netstat.
Hence, the correct answer is B.
by Judy at Feb 12, 2026, 07:08 AM
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