"/etc/init.d/networking restart" has been technically deprecated for a long time. If you ran it there was warning that all interfaces might not restart.

Ubuntu 14.04 now gives a cryptic error when trying to use it. See https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1301015

This fix is from https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1301015/comments/8 and should work on all distros