How to block sites in Firefox

Martin Brinkmann
Nov 8, 2014
Firefox, Firefox add-ons

Internet users have quite a few options at their disposal when it comes to blocking sites on the web. They can use the hosts file for example which blocks them on a system-wide level, configure firewall rules for the same effect, use a DNS provider that allows the filtering, or block specific urls or sites in a program directly.

The last option is not overly effective, especially when it comes to blocking sites so that others, children for instance, cannot access them.

It is easy enough to bypass browser-specific blocks, for instance by using a different browser or a different profile in the same browser.

Blocking sites in the browser can however be an excellent option when it comes to restricting yourself. If you don't want to visit specific sites directly or indirectly, then you can use these type of add-ons to prevent the sites from being loaded.

It is obviously pretty easy to bypass the block by disabling the add-on for the time being which makes these solutions ideal for self-restriction and less than ideal for anything else.

Minimal Site Block is a lightweight extension for Firefox that has received some low ratings even though that is not justified anymore.

The extension adds a single option to the add-on preferences that you can make use of to block sites. It supports the following filters:

  1. - Blocks the url only.
  2.* - Blocks all pages under the specified url.
  3. * - Blocks all pages that match the pattern.
  4. file://* - Block file requests.
  5. resource://* - Block resource requests.

When you visit a blocked site in Firefox, you receive the message that the site has been blocked. It won't load in the browser unless you disable the extension, uninstall it or remove the url pattern from the options page.

block site firefox

There are plenty of ways to bypass the protection including the use of a proxy server.

The extension supports different protocols. You can block https websites for example but need to specify the protocol to do so. The pattern * blocks access to the social networking sites regardless of the protocol that is being used.

It is interesting to note that it seems to block page requests to resources from blocked urls as well. If you block Facebook you will notice that social media buttons and information are not displayed on third-party sites.

Closing Words

Minimal Site Block is a handy extension for Firefox users to restrict access to specific resources on the Internet or a local network.

The blocking works fine and since it is also blocking requests on third-party sites, it is excellent to block access to certain resources completely.

software image
Author Rating
5 based on 1 votes
Software Name
Minimal Site Block
Landing Page

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  1. Dlozi said on May 29, 2016 at 6:07 pm

    Perhaps it has a low rating because it doesn’t give instructions on how to use it. I can’t figure it out

  2. Blue said on November 8, 2014 at 9:01 pm

    Without the GUI, some of us are left scratching our heads trying to figure out how to activate / edit it… When we visit the author’s support site besides trouble shooting strings, there is a link to download the JS files…. which even that was confusing as there was no way to run the script, no JSON file either so I am still scratching my head.

    Obviously I tried to see if it left an icon behind in one of my many hidden elements, or context menu, but none was found. The downloaded files did contain ICON files but with no idea how to implement and link them this may be the reason why this got so little positive reviews.

    Perhaps instead of assuming everyone would know how to activate this add-on, how about a tutorial of how to use it instead of a review that only applies to the handful who figured it out while the rest of us are still scratching our heads eh?

    1. Martin Brinkmann said on November 8, 2014 at 9:14 pm

      You edit the blocked sites in the preferences of the add-on (about:addons)

  3. jasray said on November 8, 2014 at 6:53 pm

    Over at Lifehacker today, Adam Savage offers a unique biological theory for the need to install and use and play with programs like defraggers, registry optimizer, etc. We all know they do little for performance, but by “tinkering” we are fulfilling some purpose–even though that purpose may be a symptom of existential angst and despair rather than a “deep release” of chemicals needed for happiness. Thank you, Martin, for continuing to offer us “tinker toys.”

    “There’s that human desire to tinker… Using [your hands] must be a deep release of important chemicals that make us feel like we’re fulfilling our purpose. Tinkering, for me, makes me feel like I’m fulfilling a deeply biological purpose.”
    Adam Savage

    1. InterestedBystander said on November 8, 2014 at 9:16 pm

      That’s an interesting observation. Perhaps remotely related to grooming behavior — “clean it up, get the bugs and parasites out.” I recall that when I used solely Windows there was a feeling of desperation when the OS glitched and wouldn’t boot or wouldn’t go online. I might conjecture that a few experiences like that might reinforce the urge to periodically “get the bugs and parasites out” even if the system really doesn’t need it. Maybe the continual “optimizing” becomes a magical ceremony to keep OS demons at bay.

      I notice a similar thing happening with internet security. I started tinkering with Firefox add-ons (Ghostery, NoScript, Adblock, the usual suspects), then started modifying about:config to block geolocation, DOM, phone-home crash reports, etc. Now I’m tinkering with putting browsers in a sandbox. …Even though I’m already running Linux and have a conservatively-configured firewall in place.

      The point being that my tinkering with security is a little bit of ceremonial magic: I really don’t have a deep understanding of all the possible vectors sophisticated info-gathering or intrusion schemes might use. So I tinker with extra security layers in the belief that it will keep the unknown demons away. Not really very far, psychologically, from carrying a rabbit’s foot, though pursued with a bit more critical thinking, perhaps.

    2. Martin Brinkmann said on November 8, 2014 at 7:50 pm

      Lifehacker still around? I think I have not visited that site in a year or two.

      1. jasray said on November 8, 2014 at 10:32 pm

        Yes, Gina Trapina was the crown jewel in the circle of great tech sites. LH provides a smorgasboard of offering, most of which are “reposting” of information from other sites–they really love to take Ghacks articles and information and make it their own with no attribution.

        But . . . from a business perspective and a readership “click, click” income producing site, it’s likely the most successful site online. We are talking 50,000 readership clicks on 30 articles or more each day and every click = dollars and cents.

        They must be doing something right–I mean, CREAM.

      2. deltoid said on November 8, 2014 at 8:36 pm

        the quality of LH articles has declined a lot
        in the last few years.

        I occasionally find an interesting post
        and quickly discard the rest in my RSS reader…

        Too bad…
        LH used to be great 5 years ago!

  4. Rick said on November 8, 2014 at 5:48 pm

    This is like silentblock – blocks but with no gui to make it useful.

    For silentblock, I created a small GUI interface for it, so I just copy the url and it gives me options to add url to the block list. For example, a site like ‘’, it gives me options to add either http or https, and * or * Add the selected line(s) to the block list with a click and then click the restart button and voila – done.

    You can also disable the blocklist (without disabling the addon) and of course, remove previously blocked sites from it.

    1. Ray said on November 8, 2014 at 11:58 pm

      Cool, I’ve used Silentblock on Thunderbird to block email trackers. Would be cool if you released the GUI addon!

      1. Rick said on November 9, 2014 at 5:07 pm

        No installer, no registry entries, just the one file exe

        Two firefox extensions that make this more usable: 1. External Applications Buttons (you can create a button on your FF toolbar to open the app from FF and 2. Restart 1.2.3 (an addon to restart firefox and restore the tabs .. as SilentGui requires a restart for new entries to become active (don’t shout at me – it’s SilentGui)

        You can send comments to rick_toronto@hotmail until I get some structure setup if necessary.


      2. Rick said on November 9, 2014 at 12:11 am

        I’ll do a bit of interface cleanup (I hadn’t beautified it as it was just for my use lol) and post a link back here by Nov 11

  5. XenoSilvano said on November 8, 2014 at 5:29 pm

    I wish there were an add-on where you could block sites through the right-click context menu, imputing website that you would like to block into a blacklist just seems like a chore to me.

    1. Hy said on November 8, 2014 at 6:22 pm

      I can’t find a way to do it through the right-click context menu, but the BlockSite Plus 1.1 add-on is pretty simple, and often has the site already entered for me, in which case it’s a four-click operation. If one wanted most sites blocked and not many unblocked, BlockSite Plus 1.1 can also be inverted from a blacklist to a whitelist.

    2. Martin Brinkmann said on November 8, 2014 at 5:38 pm

      It is, especially since you only have that much space in the field before it scrolls.

  6. TFd24 said on November 8, 2014 at 3:16 pm

    Unfortunately this extension works *only* with Firefox 31 and above. I suggest that Ghacks should post the version compatibility of further Firefox extensions to be featured on this very site (for the sake of Pale Moon fans and Australis haters).

    1. Martin Brinkmann said on November 8, 2014 at 5:45 pm

      The problem with reporting extension compatibility is that it changes over time.

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