How to Use the New Content Blocking Feature in Firefox

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Mozilla Firefox now has a content blocking option for privacy and security. Learn about what it is and how to use it.

After Chrome and Opera had released their new features for protecting their user’s privacy online, the developer’s favorite browser, Firefox, has now presented its version in the latest release.

Firefox has always been about giving all sorts of customization to its user base. Perhaps this is why their take is much different than Chrome and Opera who came up with a password protection system and a VPN earlier.

Mozilla has introduced Content Blocking in Firefox 65.

If you are like us, then browsers must your primary tool for accessing information online. It is only logical that the security should come by design in the very same browser as well.

Let’s see here in this article what Mozilla is talking about and how can we use this new feature to secure ourselves.

What Is Content Blocking?

Content is anything that your browser loads when it opens up a webpage. It can be some piece of code that makes the text on your screen appear in a particular way, it could be some information for the search engines which is not visible to the visitor, you, or perhaps some code that helps in the functionality of the page.

All of these things can be divided into two kinds.

  • Visible
  • Invisible

The visible portion is nothing to be worried about; it is what you and other people can see on the page. The invisible portion of the content is the code portion which may contain anything.

Most of the time, malicious webpages have pieces of code which can read anything about the current visitor, install some other piece of code to track the said visitor and perform other functions.

The simplest of these functions ranges from the mundane function of showing you ads based on your previous internet history to the more complicated, where the visitor is being tracked by phishers/hackers for due-diligence for later identity theft.

Mozilla Firefox, extending this logic, has teamed up with Disconnect to tackle the problem.

Disconnect was founded in 2011 to help fight for people’s right to online privacy. They keep track of known trackers. Firefox, with the help of this shared information, blocks them.

Firefox doesn’t block all the trackers content so that the information on the page can be displayed in a meaningful manner. You can, however, choose to completely block them if you want to.

So How Do We Do It?

The first thing you need to check is that you have Firefox 65 or a later version installed. Once you have that then all you need to do is follow the below-mentioned settings to get it done.

Content Blocking is a collection of options/settings which you set to have one of three available types of protection level.

These levels are…

·        Standard

This is the default mode of content blocking. When enabled, it affects the trackers in the private window only.

·        Strict

When you select this setting, all the trackers in all the windows are blocked as well as third-party cookies.

·        Custom

The custom setting gives you full control of what you want to block. You can choose to block the trackers or cookies or their combination if you want to.

Enabling Content Blocking

The standard mode is set by default. This means that the standard list of trackers is already being blocked in your private window.

To access the content blocking options you need to…

  1. Click the three line symbol on the top right side of the Firefox window.
  2. Here right below the option of signing in, will be the Content Blocking option with its current mode visible right in front of it (Standard as per the screenshot). Click it.


  • Once clicked, the preferences page will be opened. You can also access it by simply typing about:preferences#privacy in the address bar and pressing enter.
  • Here on this page, you will be presented with the following options to choose from:
    • Standard: Blocks known trackers.
    • Strict: Blocks all trackers that are detected by Firefox.
    • Custom: Choose what you want to block or not.
  • You will see that the Standard option is selected by default.
Content Blocking

Content Blocking

  • Here, select the option that best suits your needs.

Now the Standard and Strict level of the settings are pretty straight forward. You just need to select them and that’s it.

The Custom level, however, requires you to set some other options as well. So here is how you do it if you want to set the Custom setting.

Custom Setting

Custom setting for Content Blocking will let you select what aspect of the content you want to block. You can select a combination of trackers, tracking lists and cookies.

You can choose to unblock individual websites from being blocked as well as blocking no websites at all.

Here is how you do it:

  1. Click the Custom setting option out of the Standard, Strict and Custom setting.
  2. The Custom option will display the options for trackers, tracking list and cookies.
Custom Options

Custom Options


3. You can choose to block trackers in Private Windows only or in all windows by selecting the appropriate option from the drop-down list right in front of the Tracker checkbox.

4. Conversely, you can choose to uncheck the Trackers option to unblock all trackers.


5. You can also choose to block cookies as per your preference. The available options are right in front of the drop-down list in front of the Cookies checkbox.

6. Here again, you can choose to not block any cookies at all by unchecking the Cookies option.

Changing the Tracking List

7. In the Custom option, we can change the tracking list from Disconnect by clicking the Change block list link.

Tracker's Lists

Tracker’s Lists

8. Click the link to choose from one of the two available lists from Disconnect, a basic one which allows the websites to function properly and a strict one which blocks all known trackers.

9. Before you select the strict list, know that it may break the websites or webpages you visit in such a way that they won’t look or even function properly.

Once you have set your preferred combination of settings you can now simply open up another tab and start surfing.

Choosing to Not Use Any Content Blocking at All

Firefox blocks trackers in its default mode. This means that if you haven’t activated Content Blocking, even then the browser’s Content Blocking is turned on and set on the standard mode.

If you want to completely turn content blocking off, then you have to:

  1. Select the Custom option of Content Blocking by accessing the option as mentioned before.
  2. Here, uncheck both the Trackers and Cookies option.

And that’s it.

Enabling/Disabling Content Blocking on individual Websites

You can choose individual websites to be unblocked or blocked again from Firefox’s content blocking mechanism. You may want to do that if a website that you trust is not functioning properly because of aggressive content blocking. 

For this, you need to first know how to identify whether a site has been blocked or not.

Identifying Blocked Content

  1. Look at the left side of the address bar for a shield sign.
Shield Sign

Shield Sign

  • Click on the shield sign or the small “i” sign for information regarding the website.
  • This will expand into a panel giving you information about the website and the content being blocked.
Webpage Blocking Information

Webpage Blocking Information

  • You can further check what content was blocked, if any, by clicking on the Tracker and Cookies options under the Content Blocking header

Turn Off/On Content Blocking 

  • Right under the Cookies option, click on the Turn off Blocking for This Site option.
  • This will reload the page without blocking any content.

You may also notice that the shield sign is now shown with a strike through; showing that content blocking is now turned off for this site.

  • When you click the shield sign now, you will see the option to Turn on Blocking for This Site is now available.
  • Click it to start blocking this site again.

Note: If you have disabled blocking during private browsing session then it will be again be enabled after you have ended your session.

In normal windows, a site that you unblocked will remain unblocked until you manually enable blocking on it.

That’s all there is to content blocking offered by Mozilla at the moment.

The feature seems to be a step in the right direction when it comes to privacy and data security. It is the job of the tech companies that provide us tools to also provide us with appropriate security from using the said tools too.The only weak link in this whole system is the “known” factor of the tracker list. There are always newer, more dangerous threats out there. If you are serious about your data security, then it is best to treat this option as one of the tools in your arsenal to ward off hackers. The others should include a great antivirus and a VPN.

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