Virtual private network (VPN) ¶

A virtual private network (VPN) is a technology allowing two or more computers on different networks to communicate securely as if they were on the same network segment.

Common use cases are:

• 🐦 to by-pass (country/...) restrictions and access some websites
• 🎠 to access a company internal network
• 🌍 to create a common network between companies
• ...

There are 3 categories of VPNs:

• Remote access: connect to a remote location (see also: Split-Tunnel)
• Site-to-Site: connect geographically separated networks
• SSL: use SSL/TLS, usually used in web browsers

VPN can be implemented using

• Point-to-Point Tunneling Protocol (PPTP): an implementation based on PPP, allowing traffic to leave the network. It's considered as less-secure and more vulnerable than others.
• Layer 2 Tunneling Protocol (L2TP): implementation based on PPP used with IPSec for tunneling
• OpenVPN: usually a server generates a configuration that clients use to authenticate themselves and access the VPN network

$ sudo apt install openvpn # install
$ sudo openvpn user_config.ovpn # connect 

• ...

• L2TP/IPsec
• SSTP
• SoftEther