By Martin Stut, 2009-01-24

The German IT publishing house Heise is offering a service to create an UltraVNC client that's customized to connect to your server: (German language only). Because I often need to help other computer users by remote access, the prospect of distributing a single exe file, which is able to establish a connection without installation, was appealing. So I decided to give the service a try.

I visited the URL, entered my home dyndns address and phone number, clicked on the download button and got the customized program as ctsupport.exe (c't ist the name of a German computer magazine, published by Heise). I transferred it to a virtual Windows 2000 machine. Of course I had setup my home router to forward incoming TCP connections on port 5500 to my client PC.

On the test machine, simulating someone in want of help, I double clicked the ctsupport.exe file, selected the single available connection (my server) and got connected - but only TCP-wise. The listener on my linux box did write about the connection, but did neither open a window nor write an error message. Apparently an UltraVNC server does not cooperate with any VNC-style viewer.
A glance at the Heise documentation says: "on Linux helper PCs use vncviewer". I had tightvncviewer, so that may have caused the problem. I noticed, that I already had vncviewer installed, so I simply tried vncviewer -listen on the helper PC, but the problem persisted: TCP connection established, but no windows opening and no error message on the client (helper).

At that point I decided to give up on the Heise tool and stick with "classic" TightVNC.