Possible Causes of Pinning Failure

C.

A pinning failure on an appliance port indicates that the port has failed to correctly assign a server or appliance to the intended uplink port channel. Pinning is a process that assigns network traffic to a specific physical interface or port channel based on specific criteria, such as a source MAC address, destination MAC address, or IP address.

Out of the given options, options C and D involve VLANs, while options A and B do not. Therefore, we can narrow down the possible causes to options C and D.

Option C states that Appliance VLANs are missing duplicate global VLANs, which is unlikely to cause a pinning failure. The correct syntax for VLANs is essential in ensuring proper communication between interfaces, but it is not directly related to the pinning process.

Option D suggests that Appliance VLANs are duplicated in global VLANs. This issue could cause a pinning failure because it results in the appliance port being unable to determine the correct VLAN for traffic forwarding. When duplicate VLANs exist, traffic can become misdirected, resulting in slow network performance or even a network outage. Therefore, this is a possible cause of the pinning failure.

Therefore, option D is the most likely cause of the pinning failure.