Connect from Windows VPN Client to the VPN RA Libreswan on OCI

1. Open the "VPN Settings" and create a new VPN:
   
2.  Populate the values that you configured on the VPN RA server:
   
3. On the left side select "Change adapter options":
   
4. Navigate to the Properties of your VPN connection:
   
   
5. Navigate to the security tab and select "Allow these protocols":
   
6. Activate NATT in windows by editing the registries:

   Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PolicyAgent (https://support.microsoft.com/en-us/help/926179/how-to-configure-an-l2tp-ipsec-server-behind-a-nat-t-device-in-windows)

   
   
7. Add routes for the VCN CIDR space and enabe split tunnel in PowerShell:

   Add-VpnConnectionRoute -ConnectionName "vpn-ra-oci" -DestinationPrefix 192.168.12.0/24 Set-VpnConnection -Name "vpn-ra-oci"  -SplitTunneling $True

   ConnectionName is the name that you setup for the VPN and the DestinationPrefix is the ip address space from the VCN.

Next, navigate to the VPN connection and click on "Connect":

On the VPN-RA server i captured the packets during the connection. You can clearly see the Phase1 packets and the Phase2 and after that the ESP packets:

I demonstrated the successful connection from a Windows 10 laptop to the Remote Access VPN in OCI.