Slow network speeds with Packer

I ran into an issue using Packer this week building an Ubuntu 14.04.3 image using VirtualBox 5. If you notice slow network speeds using Packer to create your image, try specifying the nictype in your virtualbox-iso builder as per the snippet below:

"builders": [{ "type": "virtualbox-iso", "vboxmanage": [ ["modifyvm", "{{.Name}}", "--nictype1", "virtio"], ],

I picked this up from stackoverflow from a Vagrant question, but it seemed to fix my Packer issue.