Connecting to Remote Desktop using proxy and Remote Desktop Gateway?

I have setup a Remote Desktop Gateway server using Windows Server 2012 R2. I am using the Remote Desktop Gateway as an intermediary between to provide the remote desktop session over 443 since 3389 is blocked at many client locations.

However, I ran into a problem with a client who's network seems to be using an web proxy.

Is is possible to configure Remote Desktop to connect via web proxy? If so, how? If not does any one have any suggestions on how to provide a Remote Desktop session via 443 over proxy for situations where you don't control the client's PC or network? Does RemoteApps allow for access via web proxy when using RD Gateway?

The error message is below:

Your computer can't connect to the remote computer because the web proxy server requires authentication. To allow unauthenticated traffic to an RD Gateway server through your web proxy server, contact your network administrator.

Thanks for any help!

Solution 1:

As of 2008 a Microsoft employee indicated there was "no official way" to accomplish this. Given the six intervening years you'd like to think there has been progress, but I'm not seeing that there has been.

If I were in your situation I'd try to find a small Win32 HTTP/HTTPS proxy that can be "pointed" at an upstream proxy and configured to provide authentication. I don't have an immediate recommendation for such a thing. (I'd probably just throw something together with Perl or Python, personally.)

Solution 2:

Another option is to use an SSH tunnel. PuTTY, to name names, has an easily-configured proxy option, so it can work through the proxy server and then provide a local tunnel through which you can connect to the RDP destination.

This does assume that the client has something to login to via SSH, and more specifically something that can communicate with the RDP server.