[winswitch] How to setup a proxy with different computer

[Pierre Wulles]

Hello,
I need your help because I don't know how to use a proxy with xpra. I have
three machines on my network, let's call them server (ip = 1.2.3.4) , proxy
(ip = 5.6.7.8) and client (ip = 9.9.9.9).
If I want to start an app, le's say xterm on the first one and using the
second one as a proxy, what should I do ? I have tried a lot of command on
every machine but everytime it fails with error message as
xpra initialization error:
 failed to connect to '5.6.7.8:14501':
 [Errno 113] No route to host
Also I wonder if I am suppose to open port that I want to use before ?
Thank you !