APM RDP Remote resource cannot be reached

[JamesCrk]

 14.1.5.2 with APM

Hi, we have APM confiugred presenting native rdp to users. we have serval hundred users using this on a daily basis without issue, but we now have 3 users who cannot launch the rdp session and get a windows error popup "Remote resource cannot be reached". We know its related to the workstation because that same user can use a different workstation with their same accoutn and it will work.

When I packet cap on the F5 I do not see the trfafic hit the F5, so again 100% a windows issue rather than F5, but wondering if anyone came across this and know a solution? remote desktop works fine for them to other local servers etc, I cannot see anythign in eventviewer that would indicate why its failing, the cert installed on APM is a CA signed valid cert. An activeX rdp icon does work for them, but its difficult to use since it requires a few browser hacks.

Any help would be great

[lnxgeek]

If you catch the RDP file served from APM does it look right, especially the gateway configuration?

[JamesCrk]

Yes the contents are identical to the rdp file on my machine which works

[lnxgeek]

My next step would be to validate if any packages are leaving the machine with Wireshark.

If that isn't the case I think it must be related to application firewalling (or what it is called on Windows 😀) which stop the traffic from going out.

[JamesCrk · Accepted solution]

Found out it was related to registry string: RDGClientTransport

if its not present or set to 0 (which is default) it will work. if its set to 1 or 2 it will fail with that error.

[lnxgeek]

Fantastic! 😁

Do you have any documentation of this setting?

It sounds interessting.

[JamesCrk]

Just what I found on google:

The Remote Desktop Protocol v8 introduced the HTTP & UDP transports. The values for the RDGClientTransport registry key are;

• 0 (default – HTTP) (also known at “negotiate NLA using TLS”)
• 1 RPC over HTTP (also known as “RDP Security”)
• 2 RemoteDesktopGateway (WinHTTP)