Comment 4 for bug 1176248

when we ping VM from hypervisor, the hypervisor will use the shared dhcp address as source ip address. however, the ebtables rule added in https://review.openstack.org/#/c/16578/ will drop those packets who's source ip address is shared dhcp address. so we can not ping VM from hypervisor. We need to change the ebtable rules in order to allow the hypervisor to ping VM.