title: Connecting to a VPN without installation of client software
body: <p>I must sometimes write software to establish a socket with a particular server residing within a Cisco VPN. I simply write my software as if there were no VPN (making use of the standard sockets library). When it is time to run this program, I manually connect to the VPN using the client software installed on my computer, then run the program itself.</p>
  
  <p>However, it would be desirable to write the software to take advantage of a specialized socket library capable of communicating over the VPN directly, without the use of any installed client software.</p>
  
  <p>Here is some Java code illustrating the functionality I would like:</p>
  
  <pre><code>String vpnHost = ...;
  String vpnUser = ...;
  String vpnPassword = ...;
  VPNConnection vpnConnection = new CiscoVPNConnection(vpnHost, vpnUser, vpnPassword);
  
  String serverHost = ...;
  int serverPort = ...;
  Socket socket = vpnConnection.openSocket(serverHost, serverPort);
  </code></pre>
  
  <p>Is it possible to establish such a connection to a VPN without installing any client software?</p>