O comando /etc/init.d/networking restart
foi desativado em 14.04.
Para reiniciar suas interfaces, você precisa usar:
sudo ifdown eth0 && sudo ifdown eth1 && sudo ifup eth0 && sudo ifup eth1
Encontrei uma explicação para isso aqui - link :
Restarting networking on a desktop machine will cause dbus and a bunch of service to stop and never be started again, usually leading to the whole system being unusable.
As Ubuntu does event based network bring up, there quite simply isn't a way to undo it all and redo it all, so a restart just isn't plain possible. The recommended way instead is to use ifdown and ifup on the interfaces you actually want to reconfigure