(transcribed fromLoRne's page -- DavidHall)

SWANS OpenVPN

Mostly due to Chris we now have a shiny new OpenVPN based VPN.

Setup

Quick start

You may find these useful:

OpenVPN http://openvpn.net
cacert.pem - the CA certificate http://user.interface.org.nz/~agentnoel/swans.interface.org.nz.ca.pem
openvpn.conf - a suitable configuration openvpn.conf (or see below for the important bits of the file)
Your password (same as for old VPN https://user.interface.org.nz/secure/vpn/password.cgi)
tun/tap for OS X
- Tunnelblick may also work

Parameters

Just the important details -- put these into a file called 'openvpn.conf':

client
dev tun
proto udp
remote openvpn.interface.org.nz 15695
ca swans.interface.org.nz.ca.pem # 'swans.interface.org.nz.ca.pem' should be in same directory as config file
auth-user-pass
comp-lzo # may stop error message about comp-lzo

Usage

# openvpn --config openvpn.conf

Your username is the same as what you use for the Interface servers. Your password can be obtained from the location mentioned above (username/password for that page is the same as what you use for the Interface servers).

Windows Users

Windows users may have to add the following line to 'openvpn.conf':

route-method exe

source