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

Wed Oct 12 07:43:07 UTC 2011
Magicloud Magiclouds <magicloud.magiclouds at gmail.com>

  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
  I set it, too. And the problem still occurs.
  Any idea what I should check now?