In BIG-IP systems,iRules influence traffic only when they are attached to a Virtual Server. If application traffic is being sent tonodes or pool members that are not defined in the pool, this typically indicates that an iRule is overriding the default load-balancing behavior by explicitly selecting a pool or node.
According toBIG-IP Administration: Data Plane Configurationand official F5 guidance:
iRules areassociated with Virtual Servers, not directly with pools or nodes.
To determine whether an iRule is actively affecting traffic, the administrator must inspect theVirtual Server configuration.
Explanation of the correct answers:
B. Via the GUI at the Resources tab for the virtual serverTheResourcestab in the Configuration Utility displays all traffic-handling objects applied to the Virtual Server, includingassigned iRules. This is the primary GUI location to verify whether an iRule is influencing data plane traffic.
C. Via TMSH with the list /ltm virtual <virtual_server> commandThis TMSH command displays the full Virtual Server configuration, including anyiRules listed under the rules section. It is the authoritative CLI method to confirm iRule usage.
Why the other options are incorrect:
A. Via TMSH with the list /ltm rule <irule> commandThis command only shows the contents of an iRule and does not indicate whether the iRule is attached to or used by any Virtual Server.
D. Via the GUI at the iRule tab for the virtual serverBIG-IP does not provide a dedicated “iRule” tab on Virtual Servers. iRules are viewed and managed under theResourcestab.
Correct Conclusion:
To verify whether an iRule is responsible for unexpected node selection, the BIG-IP Administrator must examine theVirtual Server configuration, either through theResources tab in the GUIor by usingTMSH to list the Virtual Server configuration.
