The problem could be addressed using cygwin and vpnc opensource client.

This tutorial is suitable for people who are a little bit confortable with unix like shell or similar, I will not detail every step such as the cygwin installation steps.

Let’s begin !

P.s I based this article starting from what I’ve found here , thanks to “Salty”.

1- Install CygWin in Windows 7: http://www.cygwin.com

You should install those packages in addition to the base system:

- gcc-core

- libgcrypt-devel

- make

- perl

2- You will find on your Desktop the Cygwin link to open the bash prompt.

3- Modify the bash.exe executable to “Run as Administrator”: go to c:\cygwin\bin search bash.exe, right click on it, go to the “Compatibility” tab and flag “Run as Administrator”

4- Go to http://www.unix-ag.uni-kl.de/~massar/vpnc/ and download vpnc-0.5.3.tar.gz

5- Uncompress the tarball with the command “tar xvfz vpnc-0.5.3.tar.gz”

6- Enter the vpnc-0.5.3 directory with “cd vpnc-0.5.3″

7- Compile and install the vpnc client launcing the command “make install”

8- Download and Install OpenVPN from http://openvpn.net/index.php/open-source/downloads.html openvpn-2.1_rc20-install.exe

9- Run the OpenVPN Installater and deselct everything but TAP-Win32 Adapter V9

10- Check the Control Panel –> Network Connection and rename the TAP device as “VPN”

11- Create a configuration file in /etc/vpnc/default.conf as the following:

12- Now you have to modify the file c:\cygwin\etc\vpnc\vpnc-script-win.js, I’ve modified what I’ve found on the Theology Web site I mentioned at the top of this article.

[js]
// vpnc-script-win.js
//
// Sets up the Network interface and the routes
// needed by vpnc.

// ————————————————————–
// Utilities
// ————————————————————–

function echo(msg)
{
WScript.echo(msg);
}

function run(cmd)
{
return (ws.Exec(cmd).StdOut.ReadAll());
}

// function getDefaultGateway()
// {
// if (run("route print").match(/Default Gateway: *(.*)/)) {
// return (RegExp.$1);
// }
// return ("");
// }

function getDefaultGateway()
{
var stuff = run("route print 0.0.0.0 mask 0.0.0.0");
var res;
var inal;
//echo ("Stuff" + stuff);
if (res = stuff.match(/0.0.0.0 *(.*) 0.0.0.0 *(.*)10/)) {
// echo ("RegExp: "+RegExp.$1+"2: "+ RegExp.$2+" 3:"+RegExp.$3);
//echo ("res :" + res[0]+" THE END!!!");
inal = res[0].split(/\s/);
for (var i = 0; i < inal.length; i++) {
echo ("inal :" + inal[i]);
}

return (inal[2]);
}
return ("");
}

function getDefaultGatewayOnDisconnect()
{
var stuff = run("route print " + env("VPNGATEWAY") + " mask 255.255.255.255");
var res;
var inal;
//echo ("Stuff" + stuff);
if (res = stuff.match(new RegExp(env("VPNGATEWAY") + " *(.*) 255.255.255.255 *(.*)10","ig"))) {
//echo ("RegExp: "+RegExp.$1+"2: "+ RegExp.$2+" 3:"+RegExp.$3);
//echo ("res :" + res[0]+" THE END!!!");
inal = res[0].split(/\s/);
for (var i = 0; i < inal.length; i++) {
echo ("inal :" + inal[i]);
}

return (inal[2]);
}
return ("");
}

// ————————————————————–
// Script starts here
// ————————————————————–

var internal_ip4_netmask = "255.255.255.0"

var ws = WScript.CreateObject("WScript.Shell");
var env = ws.Environment("Process");

switch (env("reason")) {
case "pre-init":
break;
case "connect":
var gw = getDefaultGateway();
echo("Default GW: " + gw );
echo("VPN Gateway: " + env("VPNGATEWAY"));
echo("Internal Address: " + env("INTERNAL_IP4_ADDRESS"));
echo("Internal Netmask: " + env("INTERNAL_IP4_NETMASK"));
echo("Interface: \"" + env("TUNDEV") + "\"");

if (env("INTERNAL_IP4_NETMASK")) {
internal_ip4_netmask = env("INTERNAL_IP4_NETMASK");
}

echo("Configuring \"" + env("TUNDEV") + "\" interface…");

run("netsh interface ip set address \"" + env("TUNDEV") + "\" static " +
env("INTERNAL_IP4_ADDRESS") + " " + internal_ip4_netmask);

echo("Delete Default Route Output: " + run("route delete 0.0.0.0 mask 0.0.0.0"));
echo("Waiting 5 seconds to add new default route…");
run("sleep 5");
echo("Adding new VPN Default Route: " + run("route add 0.0.0.0 mask 0.0.0.0 " + env("INTERNAL_IP4_ADDRESS")));
echo("");

// Add direct route for the VPN gateway to avoid routing loops
echo("Add direct route for the VPN gateway to avoid routing loops");
echo("route add " + env("VPNGATEWAY") + " mask 255.255.255.255 " + gw);
run("route add " + env("VPNGATEWAY") +
" mask 255.255.255.255 " + gw);

echo("Checking for WINS Servers…");
if (env("INTERNAL_IP4_NBNS")) {
echo("WINS Found, adding them to the TAP Device…");
var wins = env("INTERNAL_IP4_NBNS").split(/ /);
for (var i = 0; i < wins.length; i++) {
run("netsh interface ip add wins \"" +
env("TUNDEV") + "\" " + wins[i]
+ " index=" + (i+1));
}
}

echo("Checking for DNS Servers…");
if (env("INTERNAL_IP4_DNS")) {
echo("DNS Found, adding them to the TAP Device…");
var dns = env("INTERNAL_IP4_DNS").split(/ /);
for (var i = 0; i < dns.length; i++) {
run("netsh interface ip add dns \"" +
env("TUNDEV") + "\" " + dns[i]
+ " index=" + (i+1));
}
}

echo("done.");

// Add internal network routes
echo("Configuring networks:");

if (env("CISCO_SPLIT_INC")) {
for (var i = 0 ; i < parseInt(env("CISCO_SPLIT_INC")); i++) {
var network = env("CISCO_SPLIT_INC_" + i + "_ADDR");
var netmask = env("CISCO_SPLIT_INC_" + i + "_MASK");
var netmasklen = env("CISCO_SPLIT_INC_" + i +
"_MASKLEN");
run("route add " + network + " mask " + netmask +
" " + env("INTERNAL_IP4_ADDRESS"));
}

} else {
echo("Gateway did not provide network configuration.");
}
echo("Route configuration done.");

if (env("CISCO_BANNER")) {
echo("————————————————–");
echo(env("CISCO_BANNER"));
echo("————————————————–");
}

break;
case "disconnect":
// Delete direct route for the VPN gateway to avoid
echo("Cleaning Routes…");

var gw = getDefaultGatewayOnDisconnect()
echo("DefaultGW: " + gw);

echo("route delete " + env("VPNGATEWAY") + " mask 255.255.255.255");
run("route delete " + env("VPNGATEWAY") + " mask 255.255.255.255");

echo("route delete 0.0.0.0 mask 0.0.0.0 ");
run("route delete 0.0.0.0 mask 0.0.0.0 ");

echo("route add 0.0.0.0 mask 0.0.0.0 " + gw);
run("route add 0.0.0.0 mask 0.0.0.0 " + gw);
}

[/js]

13- Now you should be ready to run the command “vpnc –no-detach”

14- You should be connected to your VPN !