tem que ser algo assim
ovs-ofctl add-flow xenbr0 "dl_src={mac-address} priority=39000 dl_type=0x0800 nw_dst={ip-address} idle_timeout=65000 action=normal"
ovs-ofctl add-flow xenbr0 "dl_src={mac-address} priority=38000 dl_type=0x0800 nw_src=ANY idle_timeout=65000 tp_dst=3389 action=normal"
ovs-ofctl add-flow xenbr0 "dl_src={mac-address} priority=38000 dl_type=0x0800 nw_src=ANY idle_timeout=65000 action=drop"