Adding a new server to a switch side triggers Err-Disabled on the connected Netscaler interface.

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Citrix ADC MPX/SDX Fortville NIC Err-Disabled when LLDP Is enabled on Peer Switch/Router

If Citrix ADC is connected to a switch/router via Fortville NIC For example 10G port on MPX 8900, interface will show UP for a moment then go to Err-Disabled state. Running "show interface" command on ADC, you can find ADC Fortville NIC is in Err-Disabled State, along with TX Stall andHang counts...