network bridge default MTU -- apparent change

[Tom Horsley]

On Thu, 11 Mar 2010 16:20:04 -0800
Joe Conway wrote:

> So I can at least work around the issue this way after starting the VM,
> but still don't understand the root cause.

The vnet0 may be coming from the "default" network that libvirt
provides. If you are using bridging for everything, you can
eradicate the default network like so:

virsh net-destroy default
virsh net-undefine default

Getting rid of the default also gets rid of the dnsmasq process
libvirt starts and other cruft you don't need for pure bridging
(like insane junk added to iptables).