Negotiate Protocol Version

[PaulW]

Hi,

Trying to connect to a client machine and in the "VNC Viewer Status for ID" I get the message "Negotiate Protocol Version" and it stays stuck there, goes no further and 0 Bytes Sent, 0 Bytes received. This is the first time connecting to another computer with it installed as a service. Could not locate a thread with a similar problem. Any ideas?

[PaulW]

Additional info, I had the person restart the instantsupport.exe and I could connect. However, if I try to install as service it will not connect and I get the "Negotiate Protocol Version" and no connection takes place. And, when the UAC triggered, no more connection! So here I am staring at the remote computer screen knowing if I run as a service I'll loose connection. What to do?

[PaulW]

I left it trying to connect and got this message eventually:

"Connection failed - Error reading Protocol Version

Possible causes:
- You've forgotten to select a DSMPlugin and the Server uses a DSMPlugin
- The selected DSMPlugin is not compatible with the one running on the Server
- The password you've possibly entered is incorrect
- Another viewer using a DSMPlugin is already connected to the Server (more than one is forbidden)"

I'm not sure if this will be an issue. I had the person run the instantsupport.exe on 2 computers on the same network and install as service for each computer. Not sure if this works into the equation?

[supercoe]

Ok, let's break it down a bit....


It's seems as though the computer you are connecting to is running Vista/7 since you mention UAC. Know that UAC prompts will cause the viewer to disconnect unless installed as a service.

It appears that you can get it to work by running InstantSupport regularly but installing the service is where the problem is. Are you logged into an account with administrative privileges? Is the computer part of a domain managed network?

The reason you are getting the "Connection failed - Error reading Protocol Version" error is because the repeater will time out the viewer connection after a period of time if there isn't a server with the same ID for it to connect to.

[PaulW]

Hi, Here is where I think the process failed for me. The remote user needs to "Right-Click" and run the instantsupport.exe file "run as administrator" to give it the privileges to install the service. This came to mind when you mentioned about using an account with Administrative Privileges!

BTW, this may be useful knowledge; if you run the Sysinternals Process Explorer, Right-Click the Properties box of the repeater108.exe process and click on the TCP/IP tab you can see what ports are being used plus it updates in real time so you can actively monitor when the remote computer is hitting the repeater.

Thanks again for your help!

[supercoe]

Hi, Here is where I think the process failed for me. The remote user needs to "Right-Click" and run the instantsupport.exe file "run as administrator" to give it the privileges to install the service. This came to mind when you mentioned about using an account with Administrative Privileges!

Ok, now everything makes sense, you should never run InstantSupport this way.

InstantSupport runs everything from the temp folder and doesn't require admin rights to function. Choosing the install service option will elevate a separate executable to install everything.

Elevating InstantSupport.exe by choosing "run as administrator" causes it to run the UltraVNC server on the secure desktop (UAC) which breaks everything.

On a side note, where did you get the idea to run InstantSupport as admin? I took a quick look at the documentation and didn't see anything that would suggest doing this.

[PaulW]

Ok, now everything makes sense, you should never run InstantSupport this way.
InstantSupport runs everything from the temp folder and doesn't require admin rights to function. Choosing the install service option will elevate a separate executable to install everything.
Elevating InstantSupport.exe by choosing "run as administrator" causes it to run the UltraVNC server on the secure desktop (UAC) which breaks everything.

Okay, you'll have to guide me through this because it only worked when I did it this way. Without elevating the Service would not install? When I had them download the file and run it normally and after that click on install service via the SYSTRAY icon I could never connect. However, when I had them "run as admin" the service did install via the SYSTRAY icon and I was able to connect and handle any UAC prompts. I would prefer the customer did not have to take this extra step?

On a side note, where did you get the idea to run InstantSupport as admin? I took a quick look at the documentation and didn't see anything that would suggest doing this.

I got this idea from your previous post in this thread where you mentioned the account needed Administrative privileges.