Firefox Privacy Setup: A Layered Approach That Actually Works
Firefox has the best privacy defaults of any mainstream browser. But "best defaults" still leaves room for improvement — the question is how much effort you want to put in and what you're actually protecting against.
Here's a layered approach: start with the easy wins, add more if you need it.
Layer 1: Built-in Settings (5 minutes)
Enhanced Tracking Protection — Firefox enables this by default. Go to Settings → Privacy & Security and check that it's set to "Strict". Standard mode blocks fewer trackers. Strict blocks more but occasionally breaks sites.
DNS over HTTPS — In Settings → Privacy & Security → DNS over HTTPS. Enable it and choose a provider (Cloudflare or NextDNS). This encrypts your DNS queries so your ISP can't see which domains you're looking up.
Telemetry — Scroll down in Privacy & Security and uncheck all the Firefox telemetry and data collection options if you don't want to contribute usage data to Mozilla.
HTTPS Only Mode — Enable this in Privacy & Security. Firefox will only connect to sites over HTTPS, and warn you before loading HTTP pages.
Layer 2: Essential Extensions
uBlock Origin — The best ad and tracker blocker. Free, open source, run by an independent developer. Install it and forget about it. Medium mode blocks most ads without breaking things; Hard mode blocks almost everything but requires some manual allowlisting.
Firefox Multi-Account Containers — Isolates your browsing by context. Cookies and sessions in one container don't leak to others. Useful for separating your work, personal, and shopping identities.
Layer 3: New Tab Considerations
Whatever extension you use for your new tab should be privacy-respecting. Some new tab extensions load analytics, serve ads, or phone home with browsing data. Check the permissions before installing.
Weather & Clock Dashboard uses your device's location API for local weather (same as your phone's weather app) and doesn't collect or transmit browsing history. It's MIT open source, so you can read the code if you want to verify.
Layer 4: Advanced (If You Need It)
arkenfox user.js — A hardened Firefox configuration file maintained by the security community. It changes hundreds of about:config settings to minimize fingerprinting and telemetry. Significantly more aggressive than the above — read the documentation before using it, as it will break some sites.
Private browser windows — Worth clarifying what these actually do: private windows prevent Firefox from saving your browsing history, cookies, and form data locally. They don't make you anonymous to websites, your ISP, or network administrators. The name is misleading for some people.
VPN — If you need to protect your IP address from websites, a VPN helps. It moves trust from your ISP to your VPN provider, so choose one with a credible no-logs policy. Mullvad and ProtonVPN are well-regarded in the privacy community.
What You're Actually Protecting Against
Different threat models call for different approaches:
- Ad tracking across sites: uBlock Origin + Multi-Account Containers handles this well
- ISP snooping on your DNS: DNS over HTTPS
- Fingerprinting by websites: arkenfox goes deep here; the basic setup offers some protection
- Local data collection by Firefox: Disabling telemetry in settings
- Other people on your device seeing your history: Private windows
Most people are in the first two categories. The standard setup (uBlock Origin + ETP Strict + DoH) covers them without meaningful friction.
The Practical Summary
Do these now:
- Set Enhanced Tracking Protection to Strict
- Enable DNS over HTTPS
- Enable HTTPS Only Mode
- Install uBlock Origin
- Install Multi-Account Containers
Do these if you want more:
- Disable Firefox telemetry
- Consider arkenfox if you have a strong threat model
This covers the vast majority of real-world privacy concerns for a regular Firefox user.