F5-CTS-LTM BIG-IP Local Traffic Manager Practice Question
You are managing an LTM and notice that some traffic is not being load-balanced as expected. You see that an iRule is applied to the virtual server. What is the most likely reason the iRule is overriding the load-balancing method?
⚠ Common exam trap
Test-takers often assume the virtual server's static load-balancing method always dictates pool selection, forgetting that procedural iRules execute first in the traffic flow.
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 iRule explicitly selects a pool or node.
iRules are processed before standard load balancing in the BIG-IP pipeline. When an iRule contains commands like 'pool' or 'node', it can explicitly select a destination server, effectively bypassing the configured load-balancing algorithm. This is a common point of confusion for administrators, as the iRule logic can override the expected behavior of the pool's load-balancing method.
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 iRule is only triggered when the pool is empty.
Why it's wrong here
iRules are triggered for every request that matches the event defined in the rule (e.g., HTTP_REQUEST). They do not wait for a pool to be empty to take effect. If the iRule contains selection logic, it will apply that logic immediately for every incoming client request.
- ✓
The iRule explicitly selects a pool or node.
Why this is correct
If an iRule uses the 'pool' or 'node' command, the BIG-IP directs the request to that specific destination, ignoring the load-balancing method assigned to the pool. This allows for powerful traffic management, such as content switching or blue-green deployments, but it also overrides the default selection algorithm.
- ✗
The load-balancing method is incompatible with iRules.
Why it's wrong here
All load-balancing methods are compatible with iRules. The issue is not compatibility, but the order of operations. The iRule executes in the request flow, and if it makes a routing decision, the BIG-IP follows that instruction, rendering the pool's load-balancing configuration irrelevant for that specific transaction.
- ✗
The iRule is disabled by the current license.
Why it's wrong here
iRules are a core feature of the LTM and are not restricted by standard licenses. If an iRule is active and applied to a virtual server, it will execute. The license does not govern whether an iRule can override load-balancing methods; it only governs the availability of the feature itself.
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.