The question: is there an env var like http_proxy that will cause Firefox to make WebSocket connections through my proxy when Use system proxy settings is selected?  I'm running Linux and connecting to the internet through a corporate proxy.  If I configure the proxy settings directly in Firefox then all of my browsing works perfectly including, specifically, https://web.whatsapp.com.However, if I set the following environment variables from ~/.profileexport http_proxy='domain_user:password@http://ms_isa_server:8080'export https_proxy=$http_proxyexport ftp_proxy=$http_proxyexport no_proxy=...and then select Use system proxy settings in Firefox then everything still works perfectly except for WebSocket connections.  Specifically I get08:48:23.027 Firefox can't establish a connection to the server at wss://w4.web.whatsapp.com/ws.1 a...when trying to use https://web.whatsapp.com.
Linux http_proxy env vars and Firefox websocket connection
environment variables;firefox;http;http proxy
It's a known bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1177909. Currently nobody is working on it.