Comment 4 for bug 1255382

I'm able to reproduce, following these steps:
# apt-get install libvirt-bin
# virsh net-start default

It seems we don't have the virtual network interface (virbr0). Even with ifconfig -a, we don't have it.

However, I can get it with:
# brctl addbr virbr0
# brctl addif virbr0 eth0

_before_ the iptables commands failures, we can see:

udevEventHandleCallback:1523 : udev action: 'add'
udevGetDeviceProperty:121 : udev reports device 'virbr0' does not have property 'DRIVER'
udevGetDeviceType:1217 : Could not determine device type for device with sysfs name 'virbr0'
udevAddOneDevice:1392 : Discarding device -1 0x77606010 /sys/devices/virtual/net/virbr0

udevEventHandleCallback:1523 : udev action: 'add'
udevGetDeviceProperty:121 : udev reports device 'rx-0' does not have property 'DRIVER'
udevGetDeviceProperty:139 : Found property key 'SUBSYSTEM' value 'queues' for device with sysname 'rx-0'
udevGetDeviceType:1217 : Could not determine device type for device with sysfs name 'rx-0'
udevAddOneDevice:1392 : Discarding device -1 0x77607ae8 /sys/devices/virtual/net/virbr0/queues/rx-0

udevEventHandleCallback:1523 : udev action: 'add'
udevGetDeviceProperty:121 : udev reports device 'tx-0' does not have property 'DRIVER'
udevGetDeviceProperty:139 : Found property key 'SUBSYSTEM' value 'queues' for device with sysname 'tx-0'
udevGetDeviceType:1217 : Could not determine device type for device with sysfs name 'tx-0'
udevAddOneDevice:1392 : Discarding device -1 0x77606d60 /sys/devices/virtual/net/virbr0/queues/tx-0