Firefox Settings Cheat Sheet for Privacy
about:config Settings
network.http.referer.defaultPolicy
Value: 2
Description: Sends the Referer header only to the same base domain, reducing data leakage when navigating between different websites.
network.http.referer.trimmingPolicy
Value: 2
Description: Trims the Referer to only include the domain, reducing the amount of information about the previous page.
media.peerconnection.enabled
Value: false
Description: Completely disables WebRTC, preventing real IP address leaks via peer-to-peer connections.
media.navigator.enabled
Value: false
Description: Disables access to camera and microphone via JavaScript, increasing privacy.
webgl.disabled
Value: true
Description: Disables WebGL to block advanced fingerprinting techniques based on 3D rendering.
privacy.resistFingerprinting
Value: true
Description: Enables fingerprinting resistance mode which encrypts Canvas data and standardizes headers and APIs to reduce browser uniqueness.
network.prefetch-next
Value: false
Description: Disables page prefetching, lowering the chance of unwanted resource access.
network.dns.disablePrefetch
Value: true
Description: Disables DNS prefetching, preventing leaks of domains that might be visited.
network.http.speculative-parallel-limit
Value: 0
Description: Disables speculative parallel HTTP connections, eliminating early connections to potential resources.
network.http.http3.enabled
Value: false
Description: Disables HTTP/3 (QUIC) to avoid unstable protocol implementations and potential bugs.
network.http.http2.enabled
Value: true
Description: Ensures usage of HTTP/2, which uses TLS 1.2+ and is more stable.
privacy.clearOnShutdown.cache
Value: true
Description: Clears browser cache on shutdown to prevent tracking via cached ETags and similar data.
privacy.clearOnShutdown.cookies
Value: true
Description: Deletes all cookies at the end of each session, preventing tracker buildup.
privacy.clearOnShutdown.offlineApps
Value: true
Description: Clears offline data (AppCache, IndexedDB, etc.) on shutdown.
privacy.clearOnShutdown.siteSettings
Value: true
Description: Resets all site-specific permissions (camera, microphone, etc.) after each session.
network.http.etag.request-same-origin
Value: false
Description: Disables ETag reuse between sessions, preventing cache-based fingerprinting.
Additional System-Level Recommendations (not via about:config)
Containerization
Run Firefox using Flatpak or Firejail to isolate the browser process and restrict file system access.
AppArmor Profile
Configure a custom /etc/apparmor.d/firefox profile to limit access to sensitive directories and system resources.
These steps complement the about:config settings by enhancing security at the system level.