First published: 10th June 2010
A Virtual Private Network (VPN) provides a secure connection between networks over an insecure network (typically the internet). A VPN works by encrypting and encapsulating data between the endpoints. Initially used as cheaper alternatives to expensive leased lines, VPNs are becoming more common, with users connecting to corporate networks from home or mobile devices.
Since about 1995, Yui Kee staff have configured a variety of VPNs. Early examples included an SSH VPN (unfortunately, only tunnelling TCP traffic and with a very limited list of ethernet drivers) and software IPSec implementations. Setting up a VPN is almost never "easy", and using endpoints from different developers or manufacturers quickly becomes confusing. Even if the endpoints support exactly the same protocols, the documentation style and terminology often makes identifying how to make the same settings at both ends guesswork. The notes here cover some more recent implementations.