static BOOL CNdisApi::SetMTUDecrement ( DWORD dwMTUDecrement );Return Value:TRUE if call was successful, FALSE otherwise
Parameters:dwMTUDecrement
System-wide MTU decrement value to set.
Remarks:
This writes the MTUDecrement REG_DWORD in the standard driver’s HKLM\SYSTEM\CurrentControlSet\Services\ndisrd\Parameters key. Updating the value requires registry write permission. The SDK describes it as a decrement of the MTU reported by the driver, useful for applications that add tunnel headers. The setter persists configuration; it does not issue an IOCTL to reconfigure a running adapter.
These registry APIs do not send an IOCTL or report when the running driver adopts a new value. Coordinate activation with your driver deployment procedure. The getter opens/creates the configuration key through RegCreateKey, so access can fail under the caller’s registry permissions. See the pinned registry implementation.