How to Build an IKEv2 VPN Server for Android (Ubuntu 22.04) This guide walks you through setting up a strongSwan VPN server that is natively compatible with Android's built-in IKEv2/IPSec MSCHAPv2 client. Step 1: Install Dependencies Update your system and install strongSwan along with the EAP plugins required for Android authentication. sudo apt update && sudo apt upgrade -y sudo apt install strongswan strongswan-pki libcharon-extra-plugins libcharon-extauth-plugins libstrongswan-extra-plugins -y Step 2: Generate PKI Certificates The server needs a Certificate Authority (CA) and a Server Certificate to prove its identity to your phone. # 1. Create CA Key and Certificate ipsec pki --gen --type rsa --size 4096 --outform pem > ~/ca-key.pem ipsec pki --self --ca --lifetime 3650 --in ~/ca-key.pem --type rsa --dn "CN=VPN CA" --outform pem > ~/ca-cert.pem # 2. Create Server K...