To use noVNC with existing UltraVNC server you need to do some simple steps. When you launch js vnc client, it will connect to websockify - websockect to tcp proxy, which will connect to your vnc server. Here are these steps:

Step 1. Configure vnc server
You should install and configure UltraVNC server on your destination machine. For example: install vnc server on Windows 7 machine with IP: and configure them to listen on 5555 port.

Now you can connect to using UltraVNC client. If your connection is successfully established you can go to the next step.

Step 2. Configuring environment for websockify

Download and install python. I have tested websockify with python 3.2.5

After installing python you should get latest version of noVNC.

Extract zip archive to C:\noVNC.

Step 3. Launching websockify

Open cmd.exe and run:

C:\Python32\python.exe C:\noVNC\utils\websockify 7777

Now open C:\noVNC\vnc.html in browser which supports websocket. Enter in Host and 7777 in port, press Connect.

You will get Server disconnected (code: 1006) error and in cmd you will see the following error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Python32\lib\multiprocessing\", line 374, in main
  File "C:\Python32\lib\multiprocessing\", line 497, in prepare
    '__parents_main__', file, path_name, etc
  File "C:\noVNC\utils\", line 1, in <module> websockify
NameError: name 'websockify' is not defined

To fix this error you should delete from C:\noVNC\utils directory and copy C:\noVNC\utils\websockify to C:\noVNC\utils\ So you will have two identical files in C:\noVNC\utils\ : websockify and

Now you could relaunch websockify and connect to your server from noVNC client.