There’s a few steps involved to get this working, but this article covers all you need to get a VPN server running on Ubuntu:
https://help.ubuntu.com/12.04/serverguide/openvpn.html
To configure a Windows VPN client, I used the OpenVPN windows client, but removed these sections from the example client config file based on other article posts related to some errors I was getting. First, removing these lines removed the userid/password prompting which I didn’t need because I was using certificates:
auth-user-pass auth-retry interact
Then this section was causing the client to hang during extablishing the connection – removing these lines got it working for me:
management 127.0.0.1 1194 management-hold management-query-passwords
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I’ve put up an article on this topic that I hope will help others:
see Setting Up an iOS 7 On-Demand VPN:
http://www.derman.com/blogs/Setting-Up-iOS-OnDemand-VPN
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