Vagrant usage behind a proxy environment

Vagrantfile

# To install the required vagrant plugin use the following command:
# $ export http_proxy ; vagrant plugin install vagrant-proxyconf --plugin-source http://rubygems.org
#
# Add or edit your file generic Vagrantfile (in place: ~/.vagrant.d/Vagrantfile)
# To apply for all your vagrant projects the HTTP-Proxy stuff
#
# Note: vagrant needs vagrant plugin vagrant-proxyconf
#
Vagrant.configure("2") do |config|
  puts "proxyconf..."
  if Vagrant.has_plugin?("vagrant-proxyconf")
    puts "find proxyconf plugin !"
    if ENV["http_proxy"]
      puts "http_proxy: " + ENV["http_proxy"]
      config.proxy.http     = ENV["http_proxy"]
    end
    if ENV["https_proxy"]
      puts "https_proxy: " + ENV["https_proxy"]
      config.proxy.https    = ENV["https_proxy"]
    end
    if ENV["no_proxy"]
      config.proxy.no_proxy = ENV["no_proxy"]
    end
  end
  # optional: can bypass issues with CA-SSL-Proxies
  #config.vm.box_download_insecure = true
end