If you know the router or the non-Microsoft DHCP server does not support the DHCP BROADCAST flag, you can set the following registry entry as follows instead of using the DhcpConnEnableBcastFlagToggle registry key.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{GUID}
Value name: DhcpConnForceBroadcastFlag
Value type: REG_DWORD
Value data: 0
Note A data value of 0 disables this registry entry. You can use this registry entry to prevent Windows Vista from using the DHCP BROADCAST flag. After you set this registry entry, Windows Vista never uses the DHCP …