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Preventing MAC Bridging on a Windows XP Host (1212)

Details

I get an error message that says a network adapter cannot be part of the Windows Network Bridge, because it may be incompatible with my local network. Why do I see this message? Do I need to make any changes to my configuration?

Solution

VMware products do not allow the Windows XP MAC Bridging feature to bridge a virtual machine's virtual network adapters to physical network adapters on the host machine. This is done to prevent the VMware DHCP Service from leaking DHCP traffic onto the physical network.

If you need to use MAC bridging with one or more virtual network adapters, you can override the MAC bridging prevention mechanism by creating an option in your Windows XP host registry called AllowBindingToMACBridge and setting it to 1.

Warning: Overriding the MAC bridging prevention mechanism may cause DHCP traffic to leak onto your physical network.

Note: Do not confuse MAC bridging with the bridged networking used for virtual machines. For information on scenarios where bridged networking may fail, see:

To set this option, do the following.

  1. Open the registry on your Windows XP host. Choose Start > Run > regedit.
  2. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class and look for the key {4D36E972-E325-11CE-BFC1-08002bE10318}.

    Make sure it is the right key by selecting it and verifying that (Default) has the value Network adapters.

    Note: This procedure modifies the Windows registry. Before making any registry modifications, ensure that you have a current and valid backup of the registry and the virtual machine. For more information on backing up and restoring the registry, see the Microsoft article 136393.

  3. Under {4D36E972-E325-11CE-BFC1-08002bE10318}, there are subkeys 0000, 0001, 0002 and so forth. Select each subkey until you find the one that corresponds to the VMnet adapter in question. The correct key has the DriverDesc with value VMware Virtual Ethernet Adapter ?.
  4. Add a DWORD value called AllowBindingToMACBridge, and set it to 1.
    1. Right-click the subkey, then choose New > DWORD Value.
    2. Type AllowBindingToMACBridge and press Enter.
    3. Right-click the new option and select Modify.
    4. In the Value date entry field, type 1.
    5. Close the registry.


    Note: If you see more than one subkey that looks like the correct VMnet adapter, VMware suggests you add the AllowBindingToMACBridge DWORD to each subkey.

Tags

cannot-add-network-addapter  incompatible-network-adapter  network-security  physical-network-adapter  reconfigure-networking  secure-network  separate-network  virtual-machine-networking

Update History

05/12/2011 - Added links to additional information. Did not re-assess article content.

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