My question was aimed at which physical/virtual ports a router listened on.
I've been trying to configure a router to send and receive VXLAN datagrams over a VRF. I can get it to send, but not receive. I've tried using the mangle to direct incoming datagrams from the VRF to the main routing table, in the expectation that the router would then be able to process them, but this has no effect.
I've fallen back to using a cross-over cable to connect two physical ports, which is a waste of ports, bit it works.