Q: Which physical network port does IPMI operate over?
A: IPMI will function over one of two ports on the motherboard integrated NIC, and utilizes a failover option to determine which interface it will use. The first port is the dedicated IPMI port, which usually sits by itself above a few USB ports on the motherboard. If this dedicated port is not plugged in, it fails over to the secondary port, known as LAN 1. The LAN 1 port sits to the bottom left of the 2-port or 4-port integrated motherboard NICs.
Note that when IPMI is in the failover mode, it broadcasts two MAC addresses over the single LAN 1 port. You can change this behavior by logging into the IPMI web interface, where you can select a single interface to use for IPMI regardless of which port is plugged in.
If you would like to change this default behavior to force only one port to respond to IPMI, change it according to the failover mode guide.