The MIB file is present in the download section of NetScaler SDX GUI.
Log on to the Downloads page of the NetScaler SDX appliance user interface.
Under SNMP Files, click SNMP v2 - MIB Object Definitions.
Note: You can open the file by using a MIB browser.
You can load the MIB file into SNMP Monitoring Server after download.
For infrmation on IPMI SNMP management information base (MIB) for LOM firmware version please refer :
https://docs.citrix.com/en-us/netscaler-hardware-platforms/mpx/netscaler-mpx-lights-out-management-port-lom/configuring-network-settings-on-lom-port.html
Citrix Documentation - https://docs.netscaler.com/en-us/sdx/current-release/manage-monitor-appliance-network-configuration/configuring-snmp-trap-destination.html