How to configure Firefox for privacy and security

Caveats

• When copy/pasting commands that start with $, strip out $ as this character is not part of the command

Setup guide

Step 1: install Firefox

Go to https://www.mozilla.org/en-US/firefox/new/, download and install Firefox.

Step 2: add user.js to profile

Heads-up: enables Mullvad DNS over HTTPS.

Heads-up: see arkenfox/user.js to explore more settings.

Start Firefox, paste “about:profiles” in address bar and press enter.

Find default profile root directory and copy to clipboard.

Download user.js to default profile root directory.

Heads-up: replace /Users/sunknudsen/Library/Application Support/Firefox/Profiles/rzrw17yo.default-release with default profile root directory copied to clipboard.

$ cd "/Users/sunknudsen/Library/Application Support/Firefox/Profiles/rzrw17yo.default-release"

$ curl --fail --remote-name https://sunknudsen.com/static/media/privacy-guides/how-to-configure-firefox-for-privacy-and-security/user.js

Step 3: restart Firefox

Step 4: install Firefox Multi-Account Containers and Privacy Badger extensions

Go to https://addons.mozilla.org/en-US/firefox/addon/multi-account-containers/ and click “Add to Firefox”.

Go to https://addons.mozilla.org/en-US/firefox/addon/privacy-badger17/ and click “Add to Firefox”.

Heads-up: when asked to allow extension to run in private windows, check box and click “Okay”.

Step 5: set default search engine to DuckDuckGo

Step 6: configure containers (see episode)

Step 7: check for DNS and WebRTC leaks

Go to https://mullvad.net/en/check.

No DNS leaks

No WebRTC leaks

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Usage guide

Temporarily disable cookie and site data deletion (useful when Firefox is restarted to install update or one wishes to reboot computer while persisting Firefox sessions)

Heads-up: “Delete cookies and site data when Firefox is closed” will be enabled again next time Firefox starts.

Start Firefox, paste “about:preferences#privacy” in address bar and press enter.

Disable “Delete cookies and site data when Firefox is closed”.

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Want things back the way they were before following this guide? No problem!

Delete user.js and set Firefox settings as they were before following guide.

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