[Answer]-Django webfaction how to open other port number?

In the Webfaction Control Panel, click on Domains/Websites -> Applications -> Add new application. In the App category pulldown, select Custom, and in App type select Custom app (listening on port). You should then see the following text (emphasis mine):

This installer assigns an unprivileged port on which custom software
can listen.

This creates the ~/webapps// directory for your convenience;
however, the custom application is not required to reside there.

After the installer has finished, configure your custom software to
listen to the port number specified in the “port” field. If the
application is configured in a website record, the front-end server
proxies incoming requests at the specified URL to the assigned port.

Note: Custom applications are intended for handling HTTP traffic. If
you need direct access to the port, please open a support ticket to
request access to the assigned port.

Custom Applications documentation is available at:
http://docs.webfaction.com/software/custom.html Website record
documentation is available at:
http://docs.webfaction.com/user-guide/websites.html

So, you’ll need to decide if your instant messaging app will communicate via HTTP or through direct access to the port, and act accordingly. To keep things simple, I’d assume you’d want to use HTTP, but the choice is up to you. Make sure you read through the custom applications documentation first, though. This will truly be a custom app, so you’ll need to write logic to check if the server is still running, restart it periodically if needed, apply cron jobs, increase number of server instance running with increases in load, etc.

Good luck!