This commit adds some additional logic that falls back to using the ifdown/ifup tools to restart networking. On Ubuntu 14.04, the init script was designed to always fail to restart newtorking, so it needs to use the ifdown/up tools instead. This commit will use the networking init script as a last resort to restart networking, assuming other commands haven't broken networking already. https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1301015
Vagrant Core Plugins
These are plugins that ship with Vagrant. Vagrant core uses its own plugin system to power a lot of the core pieces that ship with Vagrant. Each plugin will have its own README which explains its specific role.