[Users] Guest to guest multicast

Hi, I'm trying to use the VRRP protocol between two VMs, but the multicast traffic never gets through. On the oVirt host I can see the VRRP advertisements coming in for both VMs: aio:~# tcpdump -n -X -i vnet3 net 224.0.0.0/4 listening on vnet3, link-type EN10MB (Ethernet), capture size 65535 bytes 18:58:31.841220 IP 10.1.2.3 > 224.0.0.18: VRRPv2, Advertisement, vrid 1, prio 0, authtype none, intvl 1s, length 36 aio:~# tcpdump -n -X -i vnet8 net 224.0.0.0/4 listening on vnet8, link-type EN10MB (Ethernet), capture size 65535 bytes 19:02:26.907054 IP 10.1.2.4 > 224.0.0.18: VRRPv2, Advertisement, vrid 1, prio 100, authtype none, intvl 1s, length 36 What is required to enable guest-to-guest multicast communication on an oVirt node? Thanks - Frank