NAT checking for forwarded ports

lib/vagrant/action/vm/forward_ports.rb

@@ -91,6 +91,8 @@ module Vagrant
         def forward_ports(vm)
           ports = []
 
+          interfaces = @env[:vm].driver.read_network_interfaces
+
           @env[:vm].config.vm.forwarded_ports.each do |name, options|
             adapter = options[:adapter] + 1
             message_attributes = {
@@ -107,13 +109,16 @@ module Vagrant
             @env[:ui].info(I18n.t("vagrant.actions.vm.forward_ports.forwarding_entry",
                                     message_attributes))
 
+            # Port forwarding requires the network interface to be a NAT interface,
+            # so verify that that is the case.
+            if interfaces[adapter][:type] != "nat"
+              @env[:ui].info(I18n.t("vagrant.actions.vm.forward_ports.non_nat",
+                                    message_attributes))
+              next
+            end
+
             # Add the options to the ports array to send to the driver later
             ports << options.merge(:name => name, :adapter => adapter)
-
-            # TODO: Check for non-nat again... This was removed during the VBoxManage
-            # transition but should be brought back.
-            # @env[:ui].info(I18n.t("vagrant.actions.vm.forward_ports.non_nat",
-            # message_attributes))
           end
 
           @env[:vm].driver.forward_ports(ports)

lib/vagrant/driver/virtualbox.rb

@@ -227,13 +227,6 @@ module Vagrant
         results
       end
 
-      # This reads the guest additions version for a VM.
-      def read_guest_additions_version
-        output = execute("guestproperty", "get", @uuid, "/VirtualBox/GuestAdd/Version")
-        return $1.to_s if output =~ /^Value: (.+?)$/
-        return nil
-      end
-
       # This reads the list of host only networks.
       def read_bridged_interfaces
         execute("list", "bridgedifs").split("\n\n").collect do |block|
@@ -256,6 +249,13 @@ module Vagrant
         end
       end
 
+      # This reads the guest additions version for a VM.
+      def read_guest_additions_version
+        output = execute("guestproperty", "get", @uuid, "/VirtualBox/GuestAdd/Version")
+        return $1.to_s if output =~ /^Value: (.+?)$/
+        return nil
+      end
+
       # Reads and returns the available host only interfaces.
       def read_host_only_interfaces
         execute("list", "hostonlyifs").split("\n\n").collect do |block|
@@ -286,6 +286,23 @@ module Vagrant
         nil
       end
 
+      # This reads the network interfaces and returns various information
+      # about them.
+      #
+      # @return [Hash]
+      def read_network_interfaces
+        nics = {}
+        execute("showvminfo", @uuid, "--machinereadable").split("\n").each do |line|
+          if line =~ /^nic(\d+)="(.+?)"$/
+            nics[$1.to_i] = {
+              :type => $2.to_s
+            }
+          end
+        end
+
+        nics
+      end
+
       # This reads the state for the given UUID. The state of the VM
       # will be returned as a symbol.
       def read_state