# Securing Network Traffic

VPN -> Mechanism that allow you to remotely connect a host or network to an internal private network, passing the data over public channel like the Internet.

IPSec -> Internet protocol security (injunction with IPv6)

IP Packet -> Encrypt it -> Encrypt IP packet + IPSec Packet -> VPN -> tunnel -> VPN endpoint.

**IPSec** Supports two modes of operation:

1. Transport mode -> only the payload of the IP packet is encrypted, leaving IP header untouched
2. Tunnel Mode -> The entire IP packet header payload and all, is encrypted and encapsulated inside a new IP packet with new headers.

L2TP -> Later 2 Tunneling Point

The tunnel is provided by L2TP which permits the passing of unmodified packets from one network to another. The secure channel on the other hand is provided by IPSec, which provide CIA of data being passed.

OpenVPN

OpenVPN can operate over either TCP or UDP typically over port 1194.

It can either rely on layer 3 IP tunnel or a layer 2 ethernet tap.
