You may want to review that very carefully, typically if that separate network port doesn't have a live network on it that issues DHCP addresses the functionality will fall back to the port that is attached.
Oh fun. Thank you for the tip! Any sugestions on how to go about this? I'm a relative newb in these matters. Switching from MacOS to linux daily driver
Keep an eye on ports 16992-16995, 5900, 623, 664, and realize that packets destined for those ports may never become visible to the OS so you'll have to catch them in transit to the board. Another place to look at is what DHCP leases are issued by your DHCP server, conceivably the management engine could request an address for itself.