Re: Strange problem with vxlan!

From: Andreas Hartmann
Date: Sun Jan 05 2014 - 12:08:40 EST

On Fri, 3 Jan 2014 15:27:19 +0100
Andreas Hartmann <andihartmann@xxxxxxxxxxxxxxx> wrote:


> Now the problem:
> If the VM (=AP) runs e.g. Linux 3.4.x, all is working fine as expected.
> If the VM runs 3.12.x or even 3.10.x, the tunnel works fine a few minutes after creation. Afterwards it is broken.
> Broken means:
> A "dhcpcd eth0" e.g. on the notebook times out, doesn't work any more. Traces show:
> The udp-tunnel-packages sent by the STA through vxlan0 can be seen on the host / tap0, but they can't be seen on vxlan0 (if it works, they can be seen on the vxlan0 device, too).
> On the host runs Linux 3.10.x, on the STA 3.11.6.

Some more findings:

- Problem can be seen with Linux 3.7 in the AP (VM), too.
- *Problem disappears* if the bridge device br0 on the host is set to
promiscuous mode.
- Sometimes, there can be seen the warning
"notebook dhcpcd[2784]: eth0: bad UDP checksum, ignoring"
when starting dhcpcd on the notebook with br0 / host set to promiscuous
mode (nevertheless dhcpcd worked fine). I never saw this warning

Any idea how to fix the problem w/o running the bridge br0 on the host
in promiscuous mode?

Thanks for any hint,
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