I use a command line script to change among various proxies (and none). Firefox does not recognize when a proxy is turned on or fails to connect to it (no error messages), while other browsers and applications do just fine. I have tried selecting "Use system proxy settings" and "Auto-detect proxy settings for this network." My script contains these lines to activate a proxy reg add "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections" /v DefaultConnectionSettings /t REG_BINARY /d 46000000b10000000200000014000000736f636b733d3132372e302e302e313a313131311c0000002a2e6c6f63616c3b3139322e3136382e31312e2a3b3c6c6f63616c3e000000000000000000000000000000000000000000000000000000000000000000000000 /f reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings" /v ProxyEnable /t REG_DWORD /d 1 /f reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings" /v MigrateProxy /t REG_DWORD /d 1 /f The first line enables the proxy to take effect without entering inetcpl.cpl. Again, this works for any application other than Firefox. The proxies are all through ssh with port forwarding. I do not want to manually configure a proxy in Firefox, because I do not want to change this every time I need to change proxies or turn them off. This is not an acceptable solution. I am on Windows 8.1 64bit, with Firefox version 35.0 Any idea what might be going on here?