See here for adding persistent routes in Linux (ubuntu). Not only to whitelisting resources. A last alternative as far as I know would be to build an OpenVPN server (instead of IPSec) in 192.168.0.0/24 which will proxy all traffic by default. Excellent tutorial here. …
Configure a VPN tunnel between Linux and Windows XP Jun 03, 2020 Debian/Jessie: Easiest way to connect to VPN (Ipsec) For connecting to an IPsec VPN as a client, vpnc is quite easy to install and use. Our Linux users use it to connect to our PfSense IPsec VPNs. For installing it: sudo apt-get install vpnc To configure it, for instance, an IPsec VPN with PSK+Xauth authentication:
How to Set Up an L2TP/IPsec VPN Server on Linux
Start SoftEther VPN Server Manager (which runs on Windows, but it can connect to remote SoftEther VPN Server running on Linux, Mac OS X or other UNIX). On the Server Manager, you can see the "L2TP/IPsec Setting" button. Click it.
How To Setup A Site To Site VPN Connection with Strongswan Install the VPN Tool. On server A, run the following command to install strongswan. Linux: # yum … 6.4. IPsec Host-to-Host Configuration Red Hat Enterprise By default, the Red Hat Enterprise Linux implementation of IPsec uses group 2 (or modp1024) of the Diffie-Hellman cryptographic key exchange groups. Group 2 uses a 1024-bit modular exponentiation that prevents attackers from decrypting previous IPsec transmissions even if a private key is compromised. How to Configure IPSec on Windows May 13, 2019 IPSEC VPN on Ubuntu 16.04 with StrongSwan - Raymii.org