Change `instance` option to forwarding ports to `adapter` and make thoes options a hash at the end.

config/default.rb

@@ -13,6 +13,7 @@ Vagrant::Config.run do |config|
   config.ssh.timeout = 30
   config.ssh.private_key_path = File.join(PROJECT_ROOT, 'keys', 'vagrant')
 
+  config.vm.auto_port_range = (2200..2250)
   config.vm.box_ovf = "box.ovf"
   config.vm.base_mac = "0800279C2E42"
   config.vm.project_directory = "/vagrant"

lib/vagrant/actions/vm/forward_ports.rb

@@ -9,7 +9,7 @@ module Vagrant
             vm.forwarded_ports.each do |fp|
               @runner.env.config.vm.forwarded_ports.each do |name, options|
                 if fp.hostport.to_s == options[:hostport].to_s
-                  raise ActionException.new(:vm_port_collision, :name => name, :hostport => fp.hostport.to_s, :guestport => options[:guestport].to_s, :instance => options[:instance])
+                  raise ActionException.new(:vm_port_collision, :name => name, :hostport => fp.hostport.to_s, :guestport => options[:guestport].to_s, :adapter => options[:adapter])
                 end
               end
             end
@@ -30,7 +30,7 @@ module Vagrant
           logger.info "Forwarding ports..."
 
           @runner.env.config.vm.forwarded_ports.each do |name, options|
-            adapter = options[:instance]
+            adapter = options[:adapter]
 
             # Assuming the only reason to establish port forwarding is because the VM is using Virtualbox NAT networking.
             # Host-only or Bridged networking don't require port-forwarding and establishing forwarded ports on these

lib/vagrant/config.rb

@@ -77,6 +77,7 @@ module Vagrant
     class VMConfig < Base
       include Util::StackedProcRunner
 
+      attr_accessor :auto_port_range
       attr_accessor :box
       attr_accessor :box_ovf
       attr_accessor :base_mac
@@ -102,13 +103,15 @@ module Vagrant
         @provisioner = nil
       end
 
-      def forward_port(name, guestport, hostport, protocol="TCP", instance=0)
-        forwarded_ports[name] = {
+      def forward_port(name, guestport, hostport, options=nil)
+        options = {
           :guestport  => guestport,
           :hostport   => hostport,
-          :protocol   => protocol,
-          :instance   => instance
-        }
+          :protocol   => "TCP",
+          :adapter    => 0
+        }.merge(options || {})
+
+        forwarded_ports[name] = options
       end
 
       def share_folder(name, guestpath, hostpath = nil, opts = {})

test/vagrant/actions/vm/forward_ports_test.rb

@@ -81,7 +81,7 @@ class ForwardPortsActionTest < Test::Unit::TestCase
           assert_equal name, port.name
           assert_equal opts[:hostport], port.hostport
           assert_equal opts[:guestport], port.guestport
-          assert_equal opts[:instance], port.instance
+          assert_equal opts[:adapter], port.instance
           true
         end
       end