My best Firefox configuration

Firefox started in the 2002 as a free software browser, a rebirth of the older Netscape Navigator. It is the recommended browser for those who care about their online privacy along with TOR, The Onion Router. Firefox is highly configurable and can be modified to suit your needs very easily. I am writing this guide to help other Firefox users to get the most from their browser.

Start from the Beginning

Is Firefox in your desired language? If not, do the following:

1. Open "Addons" in the main menu
2. Search for your desired language pack and install it
3. Open a new tab and type about:config
4. Type intl.locale.matchOS in the filter and set it to false with a double-click, to ask Firefox not to follow the operating system language instructions.
5. Type general.useragent.locale and change it so it matches the language pack you installed.
6. Restart Firefox to finish.

Done? Now let's continue with my best Firefox configuration.

First-time users are presented with a tour of the features of the browser. After the first use, you get a standard window with Firefox's logo and a search bar.

As everybody uses search extensively these days, let's start by changing the default search option to a more private alternative.

Step by Step:

1. Type any word on the small search bar on the top right hand corner. You will see a smaller window appear as you do so.
2. Click on "change search settings" and a screen will show up.
3. Click on "add more search engines".
4. Look for Start Page, Ixquick or DuckDuckGo and add either one or the three of them to your browser.
5. On the same screen change your default search engine.
6. Optional, erase the ones you know you will not use.

Now you have a private search engine configured in your Firefox set-up. Now that we have the Firefox Preferences screen open, let's continue by optimising its options. Here is what I suggest you do:

Optimize Firefox's preferences

I recommend the following options:

General tab

+ Disable the "default browser" check. You can always check that manually.
+ Ask Firefox to show a blank page when it starts.
+ Always ask where to save the files you download. It's better to have control of what to do with your files.

Uncheck "don't load tabs until selected" unless you have a slow Internet connection.

Just in case, if in the general tab you chose to ask Firefox to reopen your previous tabs when you open the browser, you may want to consider keeping this option on to prevent your browser from slowing down in case you had many tabs open in your previous session.

We already edited the search tab, so let's continue with the Content tab.

On this one I recommend:

+ Keeping pop-up blocking on
+ Keeping the default font unless you want to customise it
+ Choose your preferred languages for web pages. It just takes a minute.

Applications tab

+ The most important editions on this one are the mailto: the PDF, and the feeds preferences. Choose the applications or methods which suit you best and next move to the next one.

Privacy tab

OK, this tab is important:

Check the first one, "Tell websites I don't want to be tracked". It will make Firefox send a signal to the server called "DoNotTrack". If the server respects that request, their tracking will be reduced on your computer.

The ideal setting for History is "Never remember history". The advantage is that it will make your browsing experience more private. The disadvantage of using it is that you will download once and again all content every time you visit a site. This may slightly slow your browsing experience down, as your browser will not keep any information from any site you visit.

If you appreciate speed and don't want that disadvantage, then my recommendation is going for the "use custom settings for history" mode with the following options:

+ Always use private browsing mode, unchecked
+ Remember your browsing and download history, unchecked
+ Remember search and form history, unchecked
+ Accept cookies from sites, checked
+ Accept third-party cookies, from visited only
+ Keep cookies until you close Firefox only
+ When using the location bar suggest only bookmarks (You are not saving your history, so there is no use of keeping that option on.)

Security tab

In the security tab you need to make some important decisions, so read carefully:

Most of the time, asking Firefox to warn you when you are trying to install an add-on is a safe choice, but asking Firefox to "block reported attack sites" and "reported web forgeries" means that Firefox will regularly download and update a couple of databases of reported sites to compare whether the page you want to see is safe or not before downloading it for you. The advantage of this is that you will be less exposed to risks while the disadvantage is that you will send a feedback to Mozilla and Google every time you encounter a reported phishing or malware site, disclosing the web page you wanted to see to them.

People who are using an insecure operating system (Windows or iOS) may want to keep these two options on, as the benefit often supersedes the privacy issue with those reports. Those who use a more secure operating system (GNU/Linux, BSD, Unix) may want to consider disabling these options for both speed and privacy.

Think about it and then choose.

Next you will see the "remember passwords for sites" option. Deactivate it. The only thing storing your passwords should be your brain.

Sync tab

Synchronization is optional, so use it if you want.

Advanced tab

OK, there are a few sub-tabs here:

On the general one, I leave the default options and only check the one that reads "warn me when websites try to redirect or reload the page". This is a privacy measure you may want to use, as it may let you see when you are being redirected to another page instead of "assuming" you consented and just take you there.

On the Data Choices, I unchecked and disable the Firefox Health Report. Long story short, it will gather some information about your browsing habits and send them to Mozilla. Are you sure you want that?

On the Network tab, keep an eye on "Your cached web content", as this is the one you will erase often to keep the privacy and speed of your browser. If you wish, try the button "Clear now" and see how it works.

Lastly, do not touch the "Certificates" section unless you know what you are doing.

Optimizing about:config

Firefox has a series of other settings which are not as obvious as the menu we just edited above. They are stored in the about:config page.

Open a new tab (change your 'new tab settings' on the top right gear icon, if you wish), and type about:config. You will receive a warning message. Click on "I will be careful, I promise" to continue. A long list of texts and a search bar on top, which is the filter.

On the filter, start typing these options and making these editions:

First, some privacy and security settings:

Deactivate WebRTC. It is a fairly new communication protocol between computers, but it can be exploited via Javascript to track your real location, making it a privacy risk.

+ Set media.peerconnection.enabled to false
+ Set media.peerconnection.turn.disable to true
+ Set media.peerconnection.use_document_iceservers to false
+ Set to false
+ Set media.peerconnection.identity.timeout to 1

Next, let's tell Firefox not to tell servers where we are (geolocation) or which page we were viewing before visiting their site. In addition, let's reduce websites' permission to store things in our computers:

+ Set network.http.sendRefererHeader to 0
+ Set network.http.sendSecureXSiteReferrer to false
+ Set network.http.speculative-parallel-limit to 0
+ Set geo.enabled to false
+ Set geo.wifi.logging.enabled to false
+ Erase the value on and
+ Set to false

Note: a few sites may not work properly if the "referrer header" or the "" value are changed. If this ever happens to you, modify the option back to its default value, 2 or true, to make that web page work. Once you finish with it, just change the setting to zero or false again to restore the privacy protection.

Next, let's disable websites' control of our clipboard or right-click context menu:

+ Set dom.event.clipboardevents.enabled to false
+ Set dom.event.contextmenu.enabled to false

These changes have the additional advantage of letting us download videos by just right-clicking on it.

Next, let's disable WebGL, as it is a potential security risk...

+ Set webgl.disabled to true

...And let's review security settings:

+ Set security.tls.version.min to 1

Next type "security.ssl3" and change everything to false except...

+ security.ssl3.ecdhe_ecdsa_aes_128_gcm_sha256
+ security.ssl3.ecdhe_rsa_aes_128_gcm_sha256
+ security.ssl3.ecdhe_rsa_aes_256_sha
+ security.ssl3.rsa_aes_256_sha

...which should remain as true.

The first one works against the SSL3 "Poodle" vulnerability, the next three against the Logjam Attack, the last ones disables RC4, an insecure encryption method. If you don't find the options, you can create them.

How do you create a new value in Firefox? You do it by right-clicking on any place of the about:config screen and then entering the submenu new.

Finally, let's enhance our privacy but removing connections to third-parties on our browser:

+ Set browser.pocket.enabled to false to deactivate Pocket
+ Erase the value of browser.pocket.api
+ Erase the value of browser.pocket.oAuthConsumerKey
+ Erase the value of
+ Erase the value of geo.wifi.uri
+ Erase the value of browser.safebrowsing.appRepURL
+ Erase the value of browser.safebrowsing.gethashURL
+ Erase the value of browser.safebrowsing.malware.reportURL
+ Erase the value of browser.safebrowsing.reportURL
+ Erase the value of browser.safebrowsing.updateURL

Ready? Next, let's work on some speed settings:

+ Set network.dns.disablePrefetch to true. Create a boolean value if you don't find it.
+ Set network.prefetch-next to false
+ Set beacon.enabled to false

Firefox has been programmed to try to guess which web page you want to see next and to start downloading its contents (prefetch) and to send a signal to the site once you stop seeing a said web page (beacon). With the options above, you disable these activities. Firefox will only open the web pages you ask it to open, saving your Internet connection for your real use.

Now let's slow down a Firefox feature to get a faster browser in the long run:

+ Create a new content.notify.ontimer boolean setting, and set it to true
+ Create a new content.notify.interval integer setting, and set it to any number above 500000
+ Set browser.sessionstore.interval to 30000 or 60000

Firefox, by default, has a 120000 value for the content.notify.interval setting, which means it will redraw the web page you want to see every 0.12 seconds. The more redraws Firefox completes, however, the longer a web page takes to load in the long run. By editing these two options, you ask Firefox to redraw every given number of microseconds. 500000 in the example above is every 0.5 seconds. If you can wait longer, then set the number higher.

In the same fashion, Firefox stores your current session (the set of web pages you have open) every 15 seconds "just in case" something happens. Slowing it down to half a minute or a full minute gets you a slightly faster overall performance.

Now let's work on some comfort settings:

+ Set browser.urlbar.clickSelectsAll to true

This will let you select all the address bar with one click.

+ Set layout.spellcheckDefault to 1

This will enable the spell checker on all form fields, not just those with more than one line.

+ Set browser.backspace_action to 2

This will deactivate the backspace key's use as a back button

+ Set browser.urlbar.trimURLs to false
+ Set browser.urlbar.formatting.enabled to false

These two will clearly show the full address of the site you visit on the address bar.

+ Set browser.showQuitWarning to true
+ Set browser.tabs.closeWindowWithLastTab to false

These two will prevent Firefox from closing if you accidentally press control+Q (instead of control+W to close a tab) or if you close the last open tab of the browser. Certainly, you can always use control+Q to exit.

+ Set to 0

This will prevent the browser to open pop-up windows of any kind, forcing it to open tabs instead.

+ Set browser.tabs.insertRelatedAfterCurrent to false

This will ask Firefox to open new tabs at the end of the queue and not next to the current window.

+ Set browser.ctrlTab.previews to true

This will ask Firefox to switch to your previous selected tab when using control+tab or control+shift+tab


Add-ons are one of the core features of Firefox. They allow you to personalize or optimize lots of things on your browser and make it fit your unique wants and needs. With so many options, however, it can be overwhelming, so this guide attempts to get as much as you can with as few add-ons as possible.

Privacy Add-ons

+ Self-destructing cookies

It destroys every cookie a web page placed in your computer as soon as you get out of the page you were in. That's good for your security.

+ uBlock or uBlock Origin

It blocks many things used by others to track you or offer you targeted advertising. It includes a dashboard and lets you select many lists of blocking alternatives.

+ Policeman or uMatrix

It lets you choose what to load and what not to load from every web page you visit. It requires some interaction from your part, but I think it works really well.

+ NoScript

A famous security suite that blocks Java, Javascript and allows you to enable them by request. It requires quite a bit of interaction in the beginning, but it is OK after a few days.

+ Redirect bypasser

Many websites place themselves in the middle of your click to another site, so they can spy and count what links are being clicked by visitors of their site. This extension lets you bypass those nosy redirections by giving you a direct link to the page you want to see.

Comfort add-ons

These add-ons have made my browsing more comfortable:

+ Hide scrollbars

Once you install this, you just won't see the scrollbars any longer

+ Auto-sort bookmarks


+ Undo closed tabs button

It gives you a button to choose which of the tabs you previously closed that you would like to reopen.

+ The Fox, only better

It hides the address bar until needed, giving you more space for the web page you want to see.

+ Snap Links Plus

This allows you to open many links with one mouse drag. It can be very time-saving sometimes.


What can you do if you need a screenshot of a web page? You do the following:

1. Press shift+f2 to open Firefox's console
2. You write screenshot --fullpage to get a screen shot of the whole page, or just screenshot to get a picture of your current viewport.

Well, that's it. This web page may be edited in the future, in case I change my ideal Firefox configuration.

Learn + Computers + General computing