Mister Disagree

Overview: L2TP/IPsec is a secure vpn tunneling protocol that allows vpn client to securely access the local network from any place. Layer 2 Tunneling Protocol (L2TP) is a tunneling protocol that does not provide any encryption or confidentiality by itself, thats where IPSec comes together as it responsible to protect the tunneling session.

Platform: Ubuntu 14 64BIT

Step by step:
Step 1: Install openswan
            #apt-get install openswan

Step 2: Configure openswan config file
            Configuration file path = /etc#ipsec.conf and ipsec.secret

Step 3: Configure ipsec.conf

Step 4: Configure ipsec.secret
Step 5: Start ipsec services
             #ipsec setup --start

Step 6: Restart
             #service ipsec restart

Step 7: Add "ucsavpn" tunnel
             #ipsec auto --add ucsavpn

Step 8: Reload ipsec.config file
             #ipsec auto --replace ucsavpn

Step 9: Listen and debug tunnel
             #ipsec whack --listen

Step 10: Establish vpn tunnel
             #ipsec whack --name ucsavpn --initiate

Step 11: Terminate vpn tunnel
             #ipsec whack --name ucsavpn --terminate