diff --git a/lib/vagrant-libvirt/action/create_network_interfaces.rb b/lib/vagrant-libvirt/action/create_network_interfaces.rb
index bedafb1..047659d 100644
--- a/lib/vagrant-libvirt/action/create_network_interfaces.rb
+++ b/lib/vagrant-libvirt/action/create_network_interfaces.rb
@@ -81,6 +81,7 @@ module VagrantPlugins
             message = "Creating network interface eth#{@iface_number}"
             message << " connected to network #{@network_name}."
             if @mac
+              @mac = mac.scan(/(\h{2})/).join(':')
               message << " Using MAC address: #{@mac}"
             end
             @logger.info(message)