📖 IT Bible

Securing Network Traffic

VPN (Virtual Private Network): A secure method of connecting a device to a private network over the internet Pasted image 20260702142038

IPsec (Internet Protocol security): A VPN protocol that was designed in conjunction with IPv6 Pasted image 20260702142136

  • ​IPsec supports two modes of operations, transport mode and tunnel mode.
    • ​When transport mode is used, only the payload of the IP packet is encrypted, ​leaving the IP headers untouched.
    • In tunnel mode, the entire IP packet, header payload and all, is encrypted and ​encapsulated inside a new IP packet with new headers. ​

L2TP (Layer 2 Tunneling Protocol): It is typically used to support VPNs

The combination of L2TP and IPsec is referred to as L2TP/IPsec and was officially standardized in IETF RFC 3193.

An example of this is OpenVPN, which uses the OpenSSL library to handle key exchange and encryption of data along with control channels.