L2TP stands for Layer 2 Tunneling Protocol. L2TP was first proposed in 1999 and is an upgrade of L2F (Layer 2 Forwarding Protocol) and PPTP (Point-to-Point Tunneling Protocol). Because L2TP itself does not provide strong encryption or authentication functions, another protocol called IPsec is usually used with L2TP.

IPsec is the security of the Internet protocol. IPsec is a very flexible end-to-end security protocol, which can authenticate and encrypt each independent IP packet in a given communication. IPsec is widely used in the Internet layer of the Internet Protocol Suite.

L2TP and IPsec are more secure than PPTP (Point-to-Point Tunneling Protocol), but it is still more suitable for anonymization than security.

L2TP sometimes has firewall issues because it uses UDP port 500 and is blocked by some firewalls.