HKLM\SYSTEM\CurrentControlSet\Services\
The NdisWan subkey stores configuration data for NDISWAN drivers supporting Remote Access Service (RAS). The NdisWan subkey appears in the registry only when RAS is installed on the computer.
NDISWAN is an intermediate-level Network Device Interface Specification (NDIS) driver that lies between a 802.3 miniport to a WAN miniport, converting NDIS packets to WAN packets. NDISWAN supports PPP protocol/link framing, compression, and encryption.