A member from EE explained some of it to me already. That L2TP relies on IPSEC for encryption, since L2TP offers only authentication in it's native form. Did I understand him correctly?
Now, how do the 2 work together????
L2TP encapsulates existing packets and sends them across the internet to the destined VPN correct? When using IPSEC, does IPSEC tunnel L2TP?