HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\
The PersistentRoutes subkey contains entries representing routes that are permanent entries in the IP routing table. Unlike active routes, which are deleted when you shut down or restart Windows 2000, permanent routes are stored in the registry and remain in the IP routing table until you remove them.
Because Windows does not create persistent routes, the PersistentRoutes subkey is empty by default. You must add persistent routes manually by using the -p switch with the Route add command at the command line. The Windows Route program, Route.exe, writes the route to the routing table and to the PersistentRoutes. To remove a persistent route from the routing table (and from the registry), use the Route delete command.
Each entry in the PersistentRoutes subkey represents one route entry in the routing table.