title: How do I get VirtualBox 4.3 to allow internal private networks from Vagrant
body: <p>The Vagrant documentation states that internal networks can be configured thus:</p>
  
  <pre><code>config.vm.network "private_network", ip: "192.168.50.4", virtualbox__intnet: true
  </code></pre>
  
  <p>However, this results in the following error:</p>
  
  <p>/Applications/Vagrant/embedded/gems/gems/childprocess-0.3.9/lib/childprocess/abstract_process.rb:36:in `initialize': all arguments must be String: ["/usr/bin/VBoxManage", "modifyvm", "0fdc3dfe-756c-4f27-864e-ed393e13e0ce", "--nic1", "nat", "--nic2", "intnet", "--intnet2", true] (ArgumentError)</p>
  
  <p>when run with VirtualBox 4.3.</p>