Firefox – How to configure proxy server settings for all users

The following configuration/customisation is intended to be used with an install deployment of Firefox.

For details of how to prepare a Firefox installation for deployment see Install and Configure Firefox silently using SCCM.

This configuration does the following:

  • Configures Proxy Server settings for all users (new and existing)


  1. Create a temporary working folder for saving the files into (for example, create C:\TEMP\Firefox)
  2. Create a new text file called ‘override.ini’ and copy in the following information:
  1. Create a new text file called ‘local-settings.js’ and copy in the following information:
pref("general.config.obscure_value", 0);
pref("general.config.filename", "mozilla.cfg");
  1. Create a new text file called ‘mozilla.cfg’ – this is where the settings are stored
  2. If you need to specify a proxy server, copy the following information into mozilla.cfg: (replace settings as required by your organisation)
//Firefox Default Settings
//set proxy server settings
 pref("network.proxy.ftp", "proxy.server.local");
 pref("network.proxy.ftp_port", 8080);
 pref("network.proxy.gopher", "proxy.server.local");
 pref("network.proxy.gopher_port", 8080);
 pref("network.proxy.http", "proxy.server.local");
 pref("network.proxy.http_port", 8080);
 pref("network.proxy.type", 1);
  1. If you want to set the ‘Auto-detect proxy settings for this network’ option for all users, instead use
//Firefox Default Settings
// set proxy settings to 'Auto-detect proxy settings for this network'
pref("network.proxy.type", 4);

These configuration files need to be copied to the following folders

  • override.ini
    %ProgramFiles(x86)%\Mozilla Firefox\browser\
  • local-settings.js
    %ProgramFiles(x86)%\Mozilla Firefox\defaults\pref
  • mozilla.cfg
    %ProgramFiles(x86)%\Mozilla Firefox\

More Firefox configurations:

Please refer to the following articles for some more common customisations:

For more information on what else can be configured in the mozilla.cfg enter “about:config” into your Firefox address bar. It will list many of the accepted configuration options which you can modify using this file.


Related Articles

4 comments on “Firefox – How to configure proxy server settings for all users

  1. Adrian, We’re using a regkey through GP to set the pac file url, it works for both IE and Chrome. Ends up in Internet Option under the connections tab.
    I’m not sure what WPAD is, I’ll check it out

    1. Hey Tom – you can use network.proxy.autoconfig_url to set a PAC file URL.

      At a (untested) guess, it would look something like this:

      pref(“network.proxy.autoconfig_url”, “http://proxy.local/proxy.pac”);

      Have you thought about using WPAD to distribute your settings, either via DNS or DHCP? It should be easier and more reliable than having to push out custom Firefox installs. It would also provide installs that people do outside of your distribution, or other browsers like Chrome/Internet Explorer etc.

    2. HI Adrian, the WPAD wouldn’t work for us, we want the PAC file to be used whether or not a user is on net or off, the URL is accessible both ways and once it’s in the registry it’s always there (unless someone removes it)

Leave a Reply

Your email address will not be published.