{
  "id": 9085692,
  "title": "Sandboxing Firefox with Firejail: a no-trace browser that can't read my files or reach my LAN",
  "url": "https://urgent.news/2026/09/22/sandboxing-firefox-with-firejail-a-no-trace-browser-that-cant-read-my",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-09-22T05:05:58.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/shaarkymoo/sandboxing-firefox-with-firejail-a-no-trace-browser-that-cant-read-my-files-or-reach-my-lan-1kbk"
  },
  "original_language": "en",
  "account": "The article discusses a method to create a \"no-trace\" browser using Firefox and Firejail, which protects users' files and network activities from being accessed or affected by malware or malicious pages. The user wanted to open links from sketchy sources without worrying about malware or data leakage. However, their initial attempts failed due to issues with Firefox profile directories.\n\nThe solution involves using a persistent sandbox profile and enabling permanent private browsing in Firefox, using a custom profile and user.js file. This allows the user to keep their extensions, themes, and logins while ensuring that their browsing activity is private and cannot persist after a session.\n\nTo make the system work, three key artifacts are created:\n\n1. A whitelist configuration file (firefox.local) that specifies only the sandbox profile directory.\n2. A user.js file that sets up permanent private browsing and anti-fingerprinting preferences.\n3. An fsand script that launches Firefox with the specified profile and settings.\n\nAdditionally, the article covers network hardening by configuring Firejail to create its own virtual network interface and configuring iptables rules to block access to the LAN. This ensures that the sandboxed browser cannot reach the user's local network, even if the host system's firewall rules are not sufficient.\n\nOverall, the method provides a secure and isolated browsing environment that preserves user privacy and protects their system from potential threats.",
  "summary": "Sandboxing Firefox with Firejail: a no-trace browser that can't read my files or reach my LAN Context I wanted one Firefox profile for \"dirty\" browsing — opening links from sketchy sources — with a hard guarantee: malware or a malicious page in that profile cannot touch the rest of my system, nothing I do there survives the session, and the profile can't even read my real browsing data. But it…",
  "key_points": [
    "Sandboxing Firefox with Firejail creates a no-trace browser",
    "Whitelist configuration file and user.js file enable private browsing",
    "Firejail creates virtual network interface to block LAN access"
  ],
  "editors_take": "This approach to sandboxing Firefox with Firejail effectively creates a private browsing environment that prevents data leakage and isolates the user's network activity from potential threats.",
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}