As a prerequisite to using this guide, and before continuing, you must make sure that you have successfully set up your own IPsec VPN server, and upgraded Libreswan to the latest version due to CVE-2019-10155. This for advanced users only. Other users please use IPsec/L2TP or IPsec/XAuth mode.
This is the next part after you successfully set up your own IPsec VPN server. Following these steps allow you to configure your Android, iOS, MacOS, and Linux machine using IPsec/L2TP VPN.
IPsec/L2TP is natively supported by Android, iOS, OS X, and Windows, so there is no additional software to install for them. Setup should only take a few minutes. For Linux users, additional L2TP network manager package needs to be installed.