Comment 4 for bug 997978

Thanks,

In order to check whether it is a qemu (perhaps virtio driver) bug or
a bug in the kernel or network utilities on the host, would you be
able to try setting up a container and checking it's networking?
There are lighter weight ways of testing this, but the simplest way
would be to:

sudo apt-get install lxc
# If having lxcbr0 bothers you, since you don't need it for this test, you
# can set LXC_AUTO=false in /etc/default/lxc and do
# "sudo stop lxc; sudo start lxc".
cat > lxc.conf << EOF
lxc.network.type=veth
lxc.network.link=br0
lxc.network.flags=up
EOF

sudo lxc-create -t ubuntu -f lxc.conf -n lxc1
sudo lxc-start -n lxc1 -d

Then log into the container's console with

sudo lxc-console -n lxc1

and, from there, periodically check the network status. If that also
loses connectivity periodically, then we know the bug is happening
below kvm.