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)

Create a temporary working folder for saving the files into (for example, create C:\TEMP\Firefox)
Create a new text file called ‘override.ini’ and copy in the following information:

[XRE]
EnableProfileMigrator=false

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");

Create a new text file called ‘mozilla.cfg’ – this is where the settings are stored
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.no_proxies_on", "localhost, 127.0.0.1, *.server.local");
 pref("network.proxy.type", 1);
 pref("network.proxy.share_proxy_settings", true); // use the same proxy settings for all protocols

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.

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

Lyle Hardin says:

Thursday, 21 May 2020 at 1:18 PM

Tom, thanks for the work. I am not understanding this as it pertains to my needs. I want to setup a proxy server for all users on a single machine. I wan to allow only a single web site to be accessed by all users. I know how to set it up for a single user, but I would like to set it up once for all users.

Thank you

Tom says:

Wednesday, 11 November 2015 at 3:51 AM

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

Tom says:

Saturday, 7 November 2015 at 3:25 AM

Adrian, do you what changes to this would be needed to use a PAC File URL?

1. itsupportguides says:
  
  Sunday, 8 November 2015 at 10:53 AM
  
  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. Tom says:
  
  Saturday, 14 November 2015 at 6:59 AM
  
  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)