For some reason, the network interfaces in ubuntu/wily64 fail to configure at boot. The interfaces are renamed during boot, with dmesg
reporting things like udev renamed network interface eth0 to enp1s0. This is apparently the result of a change in systemd. You can read about it here:
Starting with v197 systemd/udev will automatically assign predictable, stable network interface names for all local Ethernet, WLAN and WWAN interfaces. This is a departure from the traditional interface naming scheme ("eth0", "eth1", "wlan0", ...), but should fix real problems.
http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/