The data flow diagram below illustrate the principle of the VPN Portal
User logs in to a web interface where several files are generated. The user chooses to download a file named username.t2vpn and double-clicks on it (in some browsers it is possible to configure to "always open the file of this type" - this will save an extra click). If installed, our VPN Helper app (T2VPN) launches, parses the t2vpn file, extracts the VPN info (host, connection type, username and password) and initiates VPN connection. Once the connection is successful, the t2vpn file is removed for security purposes. Here is how the process looks like:
Using T2VPN app is optional, there are possibilities to use a batch file for Windows, or .mobileconfig files for iOS and MacOS machines - however executing these options require additional user actions.