# How to configure Firefox for privacy and security [](https://www.youtube.com/watch?v=s-vwthG28ks "Firefox privacy and security hardening guide (2022 revised edition)") ## 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](https://www.mozilla.org/en-US/firefox/new/) Go to [https://www.mozilla.org/en-US/firefox/new/](https://www.mozilla.org/en-US/firefox/new/), download and install Firefox. ### Step 2: add [user.js](./user.js) to profile > Heads-up: enables [Mullvad DNS over HTTPS](https://mullvad.net/en/help/dns-over-https-and-dns-over-tls/). > Heads-up: see [arkenfox/user.js](https://github.com/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. ```console $ 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](https://addons.mozilla.org/en-US/firefox/addon/multi-account-containers/) and [Privacy Badger](https://addons.mozilla.org/en-US/firefox/addon/privacy-badger17/) extensions #### Go to [https://addons.mozilla.org/en-US/firefox/addon/multi-account-containers/](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/](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](https://mullvad.net/en/check).  👍 --- ## 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”. 👍 --- ## 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. 👍