Layer 2 tunneling protocol (L2TP) doesn’t actually provide any encryption or authentication – it’s simply a VPN tunneling protocol that creates a connection between you and a VPN server. It relies on the other tools in the IPSec suite to encrypt your traffic and keep it private and secure. This protocol has a few convenient features, but certain issues prevent it from being a leading VPN protocol.
This post explains VPN protocols and how to choose the right one for the best. VPN Protocols: PPTP VS SSTP VS L2TP/IPSec VS IPSec/IKEv2 VS OpenVPN VS SoftEther VS WireGuard.