HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\
The Parameters subkey stores configuration data that applies to the TCP/IP service as a whole. This data can be overridden by settings specific to a network component that uses TCP/IP, such as a network adapter driver, or by settings specific to a service that uses TCP/IP, such as DHCP or Winsock. These component-specific entries reside in subkeys representing the component.