diff --git a/lib/vagrant/actions/vm/network.rb b/lib/vagrant/actions/vm/network.rb
index 085c1aaa4..13b928a92 100644
--- a/lib/vagrant/actions/vm/network.rb
+++ b/lib/vagrant/actions/vm/network.rb
@@ -2,6 +2,13 @@ module Vagrant
   module Actions
     module VM
       class Network < Base
+        def prepare
+          # Verify that the given network options are valid
+          runner.env.config.vm.network_options.compact.each do |network_options|
+            verify_no_bridge_collision(network_options)
+          end
+        end
+
         def before_destroy
           # We need to check if the host only network specified by any
           # of the adapters would not have any more clients if it was
@@ -55,6 +62,24 @@ module Vagrant
           end
         end
 
+        # Verifies that there is no collision with a bridged network interface
+        # for the given network options.
+        def verify_no_bridge_collision(net_options)
+          # First try to find a matching network
+          interfaces = VirtualBox::Global.global.host.network_interfaces
+          interfaces.each do |ni|
+            next if ni.interface_type == :host_only
+
+            result = if net_options[:name]
+              true if net_options[:name] == ni.name
+            else
+              true if matching_network?(ni, net_options)
+            end
+
+            raise ActionException.new(:network_collides) if result
+          end
+        end
+
         # Returns the name of the proper host only network, or creates
         # it if it does not exist. Vagrant determines if the host only
         # network exists by comparing the netmask and the IP.
diff --git a/templates/strings.yml b/templates/strings.yml
index cb5cabf06..674b5c6cf 100644
--- a/templates/strings.yml
+++ b/templates/strings.yml
@@ -142,6 +142,11 @@
   If the name specification is removed, Vagrant will create a new
   host only network for you. Alternatively, please create the
   specified network manually.
+:network_collides: |-
+  The specified host network collides with a non-hostonly network!
+  This will cause your specified IP to be inaccessible. Please change
+  the IP or name of your host only network to not match that of
+  a bridged or non-hostonly network.
 :package_include_file_doesnt_exist: |-
   File specified to include: '<%= filename %>' does not exist!
 :package_multivm: |-
diff --git a/test/vagrant/actions/vm/network_test.rb b/test/vagrant/actions/vm/network_test.rb
index 39b47576d..6856247ee 100644
--- a/test/vagrant/actions/vm/network_test.rb
+++ b/test/vagrant/actions/vm/network_test.rb
@@ -4,6 +4,36 @@ class NetworkTest < Test::Unit::TestCase
   setup do
     @runner, @vm, @action = mock_action(Vagrant::Actions::VM::Network)
     @runner.stubs(:system).returns(linux_system(@vm))
+
+    @interfaces = []
+    VirtualBox::Global.global.host.stubs(:network_interfaces).returns(@interfaces)
+  end
+
+  def mock_interface(options=nil)
+    options = {
+      :interface_type => :host_only,
+      :name => "foo"
+    }.merge(options || {})
+
+    interface = mock("interface")
+    options.each do |k,v|
+      interface.stubs(k).returns(v)
+    end
+
+    @interfaces << interface
+    interface
+  end
+
+  context "preparing" do
+    should "verify no bridge collisions for each network enabled" do
+      @runner.env.config.vm.network("foo")
+      @action.expects(:verify_no_bridge_collision).once.with() do |options|
+        assert_equal "foo", options[:ip]
+        true
+      end
+
+      @action.prepare
+    end
   end
 
   context "before destroy" do
@@ -112,29 +142,33 @@ class NetworkTest < Test::Unit::TestCase
     end
   end
 
-  context "network name" do
+  context "verify no bridge collision" do
     setup do
-      @interfaces = []
-      VirtualBox::Global.global.host.stubs(:network_interfaces).returns(@interfaces)
-
       @action.stubs(:matching_network?).returns(false)
-
       @options = { :ip => :foo, :netmask => :bar, :name => nil }
     end
 
-    def mock_interface(options=nil)
-      options = {
-        :interface_type => :host_only,
-        :name => "foo"
-      }.merge(options || {})
+    should "do nothing if everything is okay" do
+      mock_interface
 
-      interface = mock("interface")
-      options.each do |k,v|
-        interface.stubs(k).returns(v)
-      end
+      assert_nothing_raised { @action.verify_no_bridge_collision(@options) }
+    end
 
-      @interfaces << interface
-      interface
+    should "raise an exception if a collision is found" do
+      mock_interface(:interface_type => :bridged)
+      @action.stubs(:matching_network?).returns(true)
+
+      assert_raises(Vagrant::Actions::ActionException) {
+        @action.verify_no_bridge_collision(@options)
+      }
+    end
+  end
+
+  context "network name" do
+    setup do
+      @action.stubs(:matching_network?).returns(false)
+
+      @options = { :ip => :foo, :netmask => :bar, :name => nil }
     end
 
     should "return the network which matches" do
diff --git a/vagrant.gemspec b/vagrant.gemspec
index c3976e188..a72d79b40 100644
--- a/vagrant.gemspec
+++ b/vagrant.gemspec
@@ -9,7 +9,7 @@ Gem::Specification.new do |s|
 
   s.required_rubygems_version = Gem::Requirement.new("> 1.3.1") if s.respond_to? :required_rubygems_version=
   s.authors = ["Mitchell Hashimoto", "John Bender"]
-  s.date = %q{2010-07-01}
+  s.date = %q{2010-07-02}
   s.default_executable = %q{vagrant}
   s.description = %q{Vagrant is a tool for building and distributing virtualized development environments.}
   s.email = ["mitchell.hashimoto@gmail.com", "john.m.bender@gmail.com"]