ref IPsec VPN Server Auto Setup Scripts

wget https://git.io/vpnsetup -O vpnsetup.sh
nano vpnsetup.sh
[Replace with your own values: YOUR_IPSEC_PSK, YOUR_USERNAME and YOUR_PASSWORD]
sudo sh vpnsetup.sh

Settings in Windows 10

1. Right-click on the wireless/network icon in your system tray.
2. Select Open Network and Sharing Center.
3. Click Set up a new connection or network.
4. Select Connect to a workplace and click Next.
5. Click Use my Internet connection (VPN).
6. Enter Your VPN Server IP in the Internet address field.
7. Enter anything you like in the Destination name field, and then click Create.
8. Return to Network and Sharing Center. On the left, click Change adapter settings.
9. Right-click on the new VPN entry and choose Properties.
10. Click the Security tab. Select “Layer 2 Tunneling Protocol with IPsec (L2TP/IPSec)” for the Type of VPN.
11. Click Allow these protocols. Be sure to select the “Challenge Handshake Authentication Protocol (CHAP)” checkbox.
12. Click the Advanced settings button.
13. Select Use preshared key for authentication and enter Your VPN IPsec PSK for the Key.
14. Click OK to close the Advanced settings.
15. Click OK to save the VPN connection details.

Note: A one-time registry change is required before connecting. See details below.

Windows Error 809 > The network connection between your computer and the VPN server could not be established because the remote server is not responding.

to fix this error, a one-time registry change is required because the VPN server and/or client is behind NAT (e.g. home router). Refer to the linked web page, or run the following from an elevated command prompt. When finished, reboot your PC. For Windows Vista, 7, 8.x and 10

REG ADD HKLM\SYSTEM\CurrentControlSet\Services\PolicyAgent /v AssumeUDPEncapsulationContextOnSendRule /t REG_DWORD /d 0x2 /f

Restart