[CentOS-virt] Emergency help needed on host network randomly stop working.

Wed Oct 12 09:43:38 UTC 2011
Peter Peltonen <peter.peltonen at gmail.com>


On Wed, Oct 12, 2011 at 10:43 AM, Magicloud Magiclouds
<magicloud.magiclouds at gmail.com> wrote:
> Hi,
>  This is a Centos 5.5 host with one xen guest.
>  About 2 weeks ago, the host randomly lost network connection. By
> this I mean I could not connect to the services on it, or ping it.
> Also was the status of the guest.
>  From serial console, I connected to the host, trying to see what
> happened. No clue (any error messages) in messages or dmesg.
> ifdown/ifup the interface did not help, either. Only rebooting was my
> only choice.
>  Searching through Google, I got the information that some other guys
> met similar problem, and resolved by setting stp on with the bridge
> interface.
>  I set it, too. And the problem still occurs.
>  Any idea what I should check now?

So I assume that the problem occurs just with the xen domU and not
with the dom0? And your solution is to reboot the domU (not dom0)?

With loosing network you mean you cannot ping your gateway ip and/or
you   cannot ping the domU from your gw?

You are running the latest kernel/xen packages provided by centos on
your dom0 and domU?

How have you configured network on this server, can you post your
configs (vif line in dom0 config aand newtork config files from the

And you are sure you have an unique MAC address in your LAN for your domU?