How to turn-off detectportal.firefox.com

While intercepting traffic with Burp Suite I want to check HTTP requests only for the site I am auditing but there is a lot of requests to http://detectportal.firefox.com/success.txt and it is a kind of annoying for me dropping every undesired request despite I intercept this and sending to "Don't intercept request for this Host/IP Address".

Searching for information about http://detectportal.firefox.com it is a functionality that Mozilla Firefox does to verify if the browser is trapped in a captive portal. Captive portals are common in public Wi-Fi hot-spots so for some reason Firefox does that check.

For some Network or System Administrators it could be difficult dealing with it because it shows a lot of traffic from users in their networks returning inaccurate statistics about browsing time by day, week, month.

In my case it fills the HTTP history with undesired requests so the best way for me is turning it from the browser. For larger networks maybe this task could be programed through deploying a GPO or some scripts doing something like that. Anyway, in the reference link there is a proposal for a managed environment.

In a simple way there's not a check box to disable it, so we have to type in the Address bar about:config then in the Search bar type captive now we have to look for network.captive-portal-service.enabled and hit double-click on it to switch from the boolean value true to false. That's it.

As Richard Stallman said: Software is for us and and we should to know what it is doing.

Reference: https://support.mozilla.org/en-US/questions/1157121