Step 1: Install StrongSwan
sudo apt update && sudo apt install strongswan strongswan-pki libcharon-extra-plugins libcharon-extauth-plugins -y
Step 2: Generate Certificates
pki --gen --type rsa --size 4096 --outform pem > server-key.pem
pki --self --ca --lifetime 3650 --in server-key.pem --dn "CN=VPN Server" --outform pem > server-cert.pem
Step 3: Configure ipsec.conf
sudo nano /etc/ipsec.conf
Step 4: Set Up Authentication
sudo nano /etc/ipsec.secrets
Step 5: Start StrongSwan
sudo systemctl start strongswan-starter
sudo systemctl enable strongswan-starter
