OpenVPN clients on windows hosts
As mentioned earlier, OpenVPN is different from and cannot interoperate with the “SSL VPN” solutions on the market, and therefore OpenVPN must be installed on all VPN hosts. In a remote access VPN setup, many remote users will need to connect to the OpenVPN server from hosts that run Windows. To set up the OpenVPN client on a Windows machine, download and install the OpenVPN Windows Installer package from the OpenVPN Web at (http://openvpn.net/index.php/downloads.html).
After installation, the OpenVPN client is either run from the Windows command line or controlled by the OpenVPN GUI. Using the setup from the previous section as an example, if the V2 client is a Windows host, the OpenVPN client is run from the command line by issuing the command shown in the following example, using the address, certificate, and key information for your site.
Running OpenVPN from the command line
openvpn --dev tun --client --remote ip-address --ca ca-cert-filename --cert endpoint-cert-filename --key endpoint-key-filename
This command establishes a VPN tunnel with the V1 OpenVPN server shown in Remote access mode. Note that the referenced files must be in the same directory from which this command is issued. Otherwise, full paths should be used for the files.
Alternatively, to control the OpenVPN client by using the OpenVPN GUI, you must create a control file. The file must be named with the .ovpn extension, for example, vyatta.ovpn. A configuration file that corresponds to the preceding command line would look as shown in the following example (with corresponding changes for your site information).
OpenVPN configuration file
dev tun client remote 220.127.116.11 ca ca.crt cert V2.crt key V2.key
Put the configuration file and the referenced files (certificates, etc.) into the OpenVPN configuration directory. This directory is usually C:\Program files\OpenVPN\config.
Start the OpenVPN GUI, which shows an icon in the notification area of the Windows taskbar. To establish the OpenVPN tunnel, right-click the icon and select Connect from the drop-down menu. If there are multiple .ovpn configuration files, the actions for each configuration appear in the drop-down menu of each file.