I am wondering if this is just a theoretical problem, or does it occur
in real life. My simple tests are not causing ICMP to be delivered to
UDP application (over the VXLAN) but it maybe because of the compare scoring
in ICMP, or because of use of multicast versus unicast destinations.

Perhaps modify the routing of received ICMP error messages
so that ones referring to the VXLAN destination port get
routed to VXLAN rather than the socket bound to the source
port (this could be made generic).

Some one seems to have invented a protocol that abuses the
normal port number rules.

	David