F5-CTS-LTM BIG-IP Local Traffic Manager Practice Question
Exhibit
ltm pool /Common/web_pool {
members {
/Common/10.0.1.10:80 { }
/Common/10.0.1.11:80 { }
}
monitor /Common/tcp
}Refer to the exhibit. The BIG-IP LTM is configured with a simple TCP monitor. Users report that while the BIG-IP shows the pool members as 'Up', they receive a '503 Service Unavailable' error when accessing the application. What is the most likely reason for this?
⚠ Common exam trap
Candidates frequently mistake a successful TCP handshake for a healthy application. They fail to realize that if the web server process is hung but the port is open, TCP monitors report success.
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 application-level health check is missing or insufficient.
A TCP monitor only confirms that the port is open and the operating system is accepting connections, not that the application service is operational. In this case, the web server process might have crashed or be misconfigured, leading to an HTTP 503 response. The LTM treats the server as 'Up' because the TCP handshake succeeds, failing to detect the application-level failure requiring an HTTP monitor.
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 TCP monitor is configured with an incorrect port.
Why it's wrong here
If the monitor had an incorrect port, the health monitor would fail and the pool members would be marked as 'Down'. The exhibit shows the members are currently 'Up', proving that the TCP connection to port 80 is successfully completing the three-way handshake as expected.
- ✗
The pool members are not responding to the TCP SYN packets.
Why it's wrong here
The pool members are marked as 'Up', which indicates they are responding correctly to the TCP SYN packets. If they were failing to respond, the LTM would mark them as 'Down' based on the timeout and interval settings defined within the TCP monitor configuration.
- ✓
The application-level health check is missing or insufficient.
Why this is correct
The TCP monitor verifies network reachability but ignores the status of the web server software. An HTTP-based monitor is required to verify that the application returns a '200 OK' response, which would detect the 503 error being served by the underlying web application service.
- ✗
The load balancing algorithm is set to Round Robin.
Why it's wrong here
The load balancing algorithm determines how incoming requests are distributed, but it does not evaluate the health of the destination server. Even if the algorithm were changed, the underlying application issue causing the 503 error would persist regardless of which server is chosen for traffic.
Visual reference
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official F5 exam blueprint
This F5-CTS-LTM practice question is part of Courseiva's free F5 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 F5-CTS-LTM exam.