OpenVPN

How VPN Works

Virtual private networks are a way of creating "virtual networks." This allows you to use an existing network connection to establish a new network connection. Networks need not be encrypted, but a virtual private network without encryption does not give you any extra security.

VPNs become useful when you add an encryption layer on top. This enables two nodes to establish a virtual network and communicate using an end-to-end encrypted link.

Setup

Get Source

Get tarball of source code from here: https://openvpn.net/index.php/open-source/downloads.html

Get the signature of the tarball

Verify the tarball with its signature

Unzip the tarball

Pre-Build

Get a few development libraries required to build OpenVPN:

$ apt-get install libzo2-dev libpam-dev

Configure/Make/Make Install

Do the Linux source code build dance:

$ ./configure
$ make 
$ make install

Single Client: Static Key VPN Setup

Detailed instructions for setting up a static key virtual private network (VPN), the simplest arrangement for a single-client VPN:

OpenVPN/Static Key

Forcing Traffic Thru OpenVPN on Router

Useful if you want to install a router between you and your ISP, to encrypt all of your traffic and route it through OpenVPN: https://jamielinux.com/blog/force-all-network-traffic-through-openvpn-using-iptables/

Also: https://charleswilkinson.co.uk/2016/05/14/selective-routing-using-ddwrt-and-openvpn/

Nice guide from Linode too: https://www.linode.com/docs/networking/vpn/tunnel-your-internet-traffic-through-an-openvpn-server