Re: VXLAN multicast receive not working

On Thu, Nov 22, 2012 at 01:05:25AM +0100, Bernhard Schmidt wrote:

The same VXLAN domain is defined on the Nexus 1000V and a VM is attached
to it. When I send some broadcast traffic down vxlan0 (i.e. ping
10.1.1.2 which generates an ARP request) the VM sees the packet just
fine.

When I do it the other way around (the VM sends a broadcast ARP for
10.1.1.3) I see a packet coming into eth1 on the multicast group, but
vxlan0 stays silent. 

I think I found a possible reason, my vxlan interface is on top of eth1

7: vxlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue
state UNKNOWN mode DEFAULT 
    link/ether 96:06:c6:cf:a0:2e brd ff:ff:ff:ff:ff:ff
    vxlan id 12340 group 239.0.0.42 dev eth1 port 32768 61000 ageing 300 

but the multicast group is joined only on eth0

root@lxbscDA-VXLAN:~/iproute2# ip maddr
1:	lo
	inet  224.0.0.1
	inet6 ff02::1
2:	eth0
	link  33:33:00:00:00:01
	link  01:00:5e:00:00:01
	link  33:33:ff:8e:0d:c7
	link  01:00:5e:00:00:2a
	inet  239.0.0.42
	inet  224.0.0.1
	inet6 ff02::1:ff8e:dc7 users 2
	inet6 ff02::1
4:	eth1
	link  33:33:00:00:00:01
	link  01:00:5e:00:00:01
	link  33:33:ff:8e:0d:c8
	inet  224.0.0.1
	inet6 ff02::1:ff8e:dc8
	inet6 ff02::1
7:	vxlan0
	link  33:33:00:00:00:01
	link  01:00:5e:00:00:01
	link  33:33:ff:cf:a0:2e
	inet  224.0.0.1
	inet6 ff02::1:ffcf:a02e
	inet6 ff02::1

At first glance I did not spot the issue with my two weeks of C, so
someone else has to hunt this down.

Regards,
Bernhard