I used omping to test multicast between 2 KVM VMs under same physical host, and it is not working in terms of multicast (normal pings/ssh works between these 2 VMs). How to enable multicast for KVM guests running under NAT networking mode under the same physical host? Per some doc from RedHat, it would be very slow using NAT with multicast for KVM. I have to use virbr0/NAT mode since I am using wireless. So although it would be slow, it should still work, but this is not the case for me.