Using Silent Block on Android

24 Jan

So, you wanna block access to websites on your Android phone? For instance, you want to make it so you can’t go on Reddit or Facebook because both those sites are prime time-wasting tomfoolery? Cool. I can help you with that, because I just figured out how to do it myself.

There’s not that much out there in terms of ways to do this, though, and the only method I was able to find for non-rooted phones (yeah, I don’t know exactly what rooting is either) was this thing called Silent Block, an add-on for Firefox Mobile. Getting Silent Block to work was quite the puzzler for my (merely) moderately tech-savvy mind. Despite this, I succeeded, and was kind of surprised that figuring it all out was actually pretty rewarding.

If you want to get Firefox mobile and Silent Block on your Android phone, which is necessary in order to block access to specific websites of your choosing, here is what you must do:

1- Go to the Google Play store, and load Firefox Browser for Android. Install and open it.

2- In Firefox, scroll to the very bottom of the first page that opens, and select “Browse all Firefox add-ons.” Alternately, google “firefox add-ons for mobile.”


3- On the Firefox for Android Add-Ons page, enter Silent Block into the search bar. Search it.

4- Silent Block will pop up. Choose it.

5- On the Silent Block page, there will be a giant green button which says “add to firefox.” Push this button. Now, leave firefox, and make sure you close the app completely. To make sure this has happened, close all apps which are currently running. If you don’t know how to do this, go ask somebody else on the internet.


6- Re-open Firefox. If you want to double check that Silent Block loaded properly, hit your “menu” button (probably a physical button on your phone), select “tools,” then select “add-ons.” You should see Silent Block in your list of Add-ons, like so:


Cool. Now you have this add-on. Too bad it’s currently useless because the add-on doesn’t know what you want it to block.


Unfortunately Silent Block is not terribly user-friendly for the uninitiated. There are no menus, no buttons, no switches. To make it work you need to squirm around in firefox’s nasty-ass internal workings and whisper techno-secrets into the right crevices if you want anything to happen. You’ll have to do similar things to your phone. Once you know how it works, it’s pretty simple, but the designer’s website instructions are designed for people with a level of technical savvy far beyond my own. I only figured this out with about an hour of effort, and a desire to solve this puzzle by learning new stuff. HERE‘s a link to the developer’s instructions, which are probably really useful if you are awesome at computers:

Here’s the big picture of what needs to happen in order for Silent Block to actually block websites on your phone: 1) you have to create a file (or files) on your phone with a list of websites you want to be blocked, and 2) you have to tell firefox where to look for these files so that it can use them. There’s a bunch of ways this could be accomplished, but I’ll show how to do it if you connect your phone to your PC. Incidentally I have a Samsung Galaxy S3 so my instructions might not line up perfectly for your phone.

That being said, let’s make this add-on actually do something:

1) Plug your phone into your PC. Go to “My Computer” on your PC, find your phone, and open the internal memory. On my phone it’s called “sdcard0” . If you have a mac, sorry. You can probably do something equivalent but I don’t know how that works, exactly.

2) You’ll have a bunch of weird files in there. Create a new file anywhere you want, and call it whatever you want. For clarity’s sake, though, you could call it “SilentBlock directory.” Remember where you put this file, though. Here’s a picture from inside my phone’s file explorer:


3) Now, open Notepad on your PC. Save a new notepad file as “contentblock-regex.txt” (without the quotations). YOU MUST NAME THIS FILE contentblock-regex.txt OR IT WILL NOT WORK. Any other file name (except for properly numbered files with the same name, to be addressed in a second) will not function. Save this .txt file in “SilentBlock directory” or whatever file you made for this purpose on your phone.

Bonus fact: To the best of my knowledge you only need one file, but if you want to have a couple files, you have to name them “contentblock-regex.txt, contentblock-regex1.txt, contentblock-regex2.txt”… and so on consecutively. I think if you don’t number them consecutively (starting with no number) it may screw stuff up. Here are some properly named files in my phone:


4) In notepad, in your .txt file which you just created and named properly, type in any websites that you want to be blocked. Here’s what my list looks like (the reason it looks different from your notepad file on the computer is because it’s opened in my phone):


Shameful sites to be time wasters, I know. But guess what- I don’t go to those sites anymore. I just put a single line break between each of the entries, and this is working for me.

5) you don’t need to put in a full URL. To my understanding, Silent Block will block anything that has that exact combination of letters and numbers in it. For instance, I just discovered that I have unintentionally blocked not only, but also by putting “” on the list. If I just put “ign” on the list, I also wouldn’t be able to go to, or to any site that has the letters “ign” anywhere in the URL. In other words, be careful! I’ve just changed my .txt file to read “” so that it blocks only the website that I want. Here’s what it looks like now.


Incidentally I have never gone to or before, but… what if I want to some day?

6) Anyways, you have put all the URLs you want to block in your contentblock-regex.txt file, we need to tell firefox where to find this file. This way, firefox can access your list, allowing Silent Block to stop your browser from going to these sites.

7) Write down where your SilentBlock directory file is. For me, it’s under “/storage/sdcard0/SilentBlock directory” (without the quotation marks). The format- with slashes, capitalization, spelling and all- is very important. On my phone this “file path” is written at the top of the screen (see picture below). We’ll be using this file path to tell firefox where to find its information about the websites we want it to block. Don’t just assume that my file path will work for you; you’ll need to figure out what your own is. If you don’t write the file path properly, Firefox will still work properly, but it will give you an error notice when it opens and no sites will be blocked.


8) After your’ve taken note of the filepath, open firefox. In the address bar, type “about:config” This opens up the guts of firefox so you can modify it as you please. I don’t understand anything about this aside from what I’m telling you right now, so don’t tinker with anything other than what I mention unless you are much more wise than I.


9) In the “search settings” box, type (without quotation marks) “extensions.silentblock.altdir” . There will be 2 buttons that pop up: Modify, and Reset. Hit Modify. In the picture provided my filepath is already there, but by hitting modify, you’ll be able to put your relevant filepath in.


10) Put in your file path. Press “okay”.

11). Now completely quit Firefox again.

12) Re-start firefox. Type in one of the webpages you want to block. If this process has worked, it simply won’t go to that page- no pop-ups, no warnings, nothing.

13) If it worked, feel like a boss. Test the other pages if you want. Enjoy

Additional steps (some of which are optional)

14) If you haven’t done so already, take up Brazilian Jujitsu.

15) If you are computer-savvy, make something that does a similar job to silent block, but make it more accessible. Charge a small fee, and make money. I don’t doubt there will be more demand for this type of thing as more people get online with their phones.

16) Go to and say thanks to the guy who made Silent Block.

16) Age for an indeterminate number of years.

17) Experience death, and (hopefully) simultaneous satisfaction with how you spent your life.



17 Responses to “Using Silent Block on Android”

  1. Jeremy February 27, 2013 at 5:19 am #

    Hat tip.

  2. Mike March 30, 2013 at 12:14 pm #

    Great article – would not have been able to configure Silent Block without it!

  3. freightmonkey June 15, 2013 at 4:33 pm #

    Very detailed tutorial, but unfortunately missing one very important point – the strings of text in the file are *regular expressions*, which means the matching doesn’t work quite the way that you imply. For instance, those “.” characters are functioning as wild cards, which means that “” would match and so on, and just putting something like “reddit” in there will block ANY URL REQUEST that contains that sequence of letters ANYWHERE in the entire url, which is probably not what you want. To avoid false positives, use something like


    (the “\” character escapes the special meaning of “/” and “.”).

    See wikipedia for more on regex basics, for a great feeling of accomplishment and to avoid setting booby traps for yourself. 🙂

    • beefhat June 17, 2013 at 10:11 pm #

      Thanks for the clarification! Because I’m lazy I probably won’t update the initial post, but I will hope people notice your comment. Also, this:


    • liquid June 10, 2017 at 6:07 am #

      Thanks a lot for your valuable comment.

  4. faithietaylor April 19, 2014 at 9:01 pm #

    I have tried this countless times now and no matter what I do I cannot get my phone to see the file.

    • beefhat April 25, 2014 at 9:47 am #

      Hi, just a couple quick thoughts: 1) are you using firefox? 2)do you have silent block installed? 3) did you save your contentblock-regex.txt file to SDcard0?

  5. Zoe June 25, 2014 at 2:57 am #

    Thank you so very much!! It actually worked!
    I’m feeling like Godzilla now 😀

  6. Lizzy September 1, 2014 at 4:29 pm #

    Cheers man. I spent hours to figure this out. Didn’t quite know where to look for the about:config. I was looking for a menu option and would have never figured out to just put this in the addres bar. Cheers for that. It works wonderful.

  7. Pedro Fonseca August 9, 2015 at 8:41 am #

    Can’t seem to get past the about:config part, the modify button never shows up.

    Posted the question here (, but was hoping someone on this forum might be able to help.


    • beefhat August 16, 2016 at 12:48 pm #

      Hi Pedro,

      Thanks for the comment. Unfortunately, this guide is pretty old, now, so it may be the case that Firefox has changed something. Or, maybe it’s your phone. In any case, I hope your forum question yields the results you need.

      If you find a fix, feel free to come back and post about it. If other people are encountering this issue, maybe mention it. If it pops up often enough I may look into it and update the guide.

      • luke May 14, 2017 at 5:24 am #

        This is an issue for me on android 5.0 and the googling for answers is making my head explode.

        I have a phone which is hard to root so I wanted to make this extension my replacement for /etc/hosts.txt

        Oh well, let the procrastination commence.

  8. jan November 17, 2016 at 9:23 pm #

    After countless unsuccessful attempts using at least five other platforms I finally managed to block Facebook.
    Thank You Sir for taking the time to explain this and thus saving me from wasting endless pointless hours in the swamp which is facebook…

  9. mmarvick April 11, 2017 at 12:14 am #

    Hey, thanks for the article! This worked great.

    I did need to make one additional step and grant Firefox with the Storage permission. I did so by going into the App Settings for Firefox, going to Permissions, and turning on the permission for Storage. Permissions were added in Android 6.0 (Marshmallow), so anyone on that version or higher will need to do this.

  10. liquid June 10, 2017 at 6:09 am #

    Thanks that was very helpful!

  11. akmere October 5, 2017 at 5:19 pm #

    Greatings, you are the hero!


  1. Firefox for Androd: can't modify anything on about:config - BlogoSfera - August 9, 2015

    […] am trying to install and configure an extension on firefox for Android. I’ve been following these instructions, which work fine until I have to alter the filepath in […]

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: