Re: pv_ops routing problem?

[Jeremy Fitzhardinge <jeremy@goop.org>]

On 04/27/2010 02:22 PM, Michael D Labriola wrote:
> Ok, I've got a problem.  My current setup is as follows:
>
> I have a pv_ops dom0 (xen/master from a few weeks ago) running 3 domUs. 
> Each domU has an eth0 interface and one or more VLAN interfaces.
>
> vm1, vm2, and vm3 are all domUs running with the same pv_ops kernel as 
> dom0.  vm1's eth0.107 interface routes through vm3 to get to vm2's 
> eth0.1020 interface.
>
> dom0:
>   eth0:     192.168.1.20/24
>
> vm1:
>   eth0:     192.168.1.10/24
>   eth0.107: 10.7.1.1/16
>   gateway:  10.7.0.1
>
> vm2:
>   eth0:      192.168.1.11/24
>   eth0.1020: 10.20.1.1/16
>   gateway:   10.20.0.1
>
> vm3:
>   eth0:      192.168.1.12/24
>   eth0.107:  10.7.0.1/16
>   eth0.1020: 10.20.0.1/16
>
>
> >From vm1, I can ping the gateway (10.7.0.1) and vm3's 1020 interface 
> (10.20.0.1), but get no response if I try to ping vm2's 10.20.1.1.
>
> vm3 can ping both 10.7.1.1 and 10.20.1.1.
>
> Should be a pretty simple packet forwarding example, and it used to work 
> using the old xen-linux 2.6.18 kernel we were using on our deployed 
> systems.  But now it's broken...
>
> I have verified that the exact same setup running on 3 physical PCs 
> bare-metal works w/out any problems.  I had the problem initially on Xen 
> 3.4.2, but just upgraded to 4.0.0 and have the exact same symptoms.
>   

Have you tried turning off tx checksum offload?  (ethtool -K <dev> tx off)

Though for me that just fixes network access between dom0 and domU;
external traffic normally works fine.

    J