VPN security - if you want it, come and get it
Attention WiFi hotspotters: You want it
Step 3: Installing and configuring OpenVPN
Navigate to OpenVPN's downloads page and download the software that fits your machine. In most instances, you'll want to download the most recent stable release of the installer, which for Windows, at time of writing, was the OpenVPN-2.1_rc9-install.exe.
Download the most recent stable release
Install the program on both the server and client. Be sure to accept all defaults options during installation. If Windows XP displays a message warning that a "TAP-Win32" adapter or "ZRTP Miniport" haven't passed logo testing, don't worry. Just click "Continue anyway" each time the message is shown.
Time to Manage the Keys
OpenVPN gives you the option to use a symmetrical key for the server to authenticate itself to the client and vice versa. This makes the key management significantly easier, but it also diminishes significantly the security of the entire system by eliminating a powerful feature known as perfect forward secrecy. So whatever you do, DON'T USE THE SYMMETRICAL KEY OPTION.
Instead, use OpenVPN's public key infrastructure (PKI), which is much harder for intruders to break. You'll need to generate a certificate authority and separate keys for the server and each client that connects, but the increased security far outweighs the extra work.
Generating and distributing the SSL keys needed for OpenVPN isn't the most intuitive of tasks but thanks to the set of key management scripts included with the OpenVPN package you just installed, you have everything needed to get the job done. To access them, go to the machine that will act as the server and open up a command window (by choosing Start > Run and typing cmd and hitting enter) and type "cd \Program Files\OpenVPN\easy-rsa" (minus the quotes, here and throughout this manual). Your command prompt should now read: "C:\Program Files\OpenVPN\easy-rsa>". Now type the following commands:
init-config vars clean-all build-ca
The first three commands will generate little in the way of a response from your computer. But after typing the last command, you'll be prompted for all kinds of information including your two-letter country code, and state or province. Feel free to enter in the correct information, or leave most of it as is. The only field that must be entered is the Common Name. Enter something like OpenVPN-CA. Congratulations, you have just created your certificate authority key.