Firefox for Enterprise Community Forum

Hello Everyone,

I am seeking assistance to configure Firefox browser so that internet access is blocked when the browser cannot download or access the proxy Auto-configuration (PAC) file. Our organisation enforces all web traffic through proxy servers defined by a PAC file. For compliance and security reasons, users should not have any direct internet access unless the browser is able to successfully retrieve and apply the PAC file.

The desired behaviour is:

1. Firefox attempts to download the PAC file from a defined URL. 2. If the PAC file is unreachable or fails to load (e.g., due to network restrictions or the device being outside the corporate network), Firefox should "fail closed" - meaning it should not allow any direct internet traffic. 3. This is effectively a "fail-block" mode: no fallback to direct connections, and no cached or bypassed proxy settings should allow internet browsing.

This behaviour is critical to prevent devices from accessing the internet without applying corporate proxy rules. I would like to know:

1/ Whether Firefox currently supports a setting or policy that enforces this fail-block condition when the PAC file is unavailable. 2/ If not, whether there are recommended configurations or enterprise policies (e.g., via `policies.json` or Group Policy templates) that could achieve equivalent enforcement.

Thank you for your assistance and guidance.

How to get rid of "Your browser is being managed by your organization"? This thing is driving me crazy(er)! Please 'dumb down' your reply, as I am not computer literate. If it's a malicious attack, my anti-virus is not picking it up. Thanks!

The recommended methods, changing to this in the registry :

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Mozilla\Firefox\Certificates] "ImportEnterpriseRoots"=dword:00000000

Reverts back to 00000001

Put this policies.json and did nothing: {

 "policies": {
   "Certificates": {
     "ImportEnterpriseRoots": false
   }
 }

} What am I missing or what's changed?

My specific need at the moment is to add another search engine option in about:preferences#search

Thanks.