Domain Sniffer

Domain Sniffer is a lightweight cross-browser extension designed for network administrators.

🌟 Why I Built This

Whitelisting is often a game of trial and error. To keep a computer truly locked down, you need to block everything by default—but modern websites rely on dozens of third-party domains (CDNs, APIs, etc.) to function.

I created Domain-Sniffer to take the guesswork out of parental controls and secure environments. It allows you to parse network traffic logs and instantly identify the "hidden" domains required to make a specific service work, ensuring a high-security posture without breaking essential tools.

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Example

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Extension

When browsing the web with strict filtering (using tools like AdGuard Home, Pi-hole, or NextDNS), websites often break because they rely on hidden background requests to external domains. Identifying which specific domains are required to fix a broken site can be tedious.

Domain Sniffer listens to the network traffic of your active tab and provides a clean, grouped list of every Root Domain and Sub-domain being requested.

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🚀 Quick Install

Chrome / Brave / Edge

1. Click here to download the Chrome ZIP.
2. Unzip the file to a folder.
3. Go to chrome://extensions.
4. Enable Developer Mode (top right).
5. Click Load unpacked (top left) and select the folder you unzipped.

Firefox

1. Click here to download the Firefox ZIP.
2. Go to about:debugging.
3. Click This Firefox (left sidebar).
4. Click Load Temporary Add-on....
5. Select the downloaded .zip file directly.

(Note: If you want to view all release notes, visit the Releases Page.)

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Features

• Real-time Sniffing: Captures network requests as they happen.
• Smart Grouping: Automatically organizes sub-domains under their root domain.
• Privacy First: Runs entirely locally. No data is sent to the cloud.
• Cross-Browser: Supports Google Chrome, Brave, Edge, and Mozilla Firefox.
• Copy to Clipboard: Easily copy the list to paste into your DNS allowlist configuration.

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🛠️ Installation from Source (Developers)

If you prefer to verify the code or contribute, you can run from source:

1. Clone this repository:

    git clone https://github.com/j86schroeder/domain-sniffer.git
   

Chrome Source Install

1. Go to chrome://extensions and enable Developer Mode.
2. Click Load unpacked.
3. Select the domain-sniffer folder.

Firefox Source Install

1. Go to about:debugging -> This Firefox.
2. Click Load Temporary Add-on....
3. Select the manifest.firefox.json file inside the domain-sniffer folder.

Note: Firefox requires a specific manifest ID, which is why we select manifest.firefox.json instead of the standard manifest.json when loading from source.

Privacy & Permissions

This extension requires the following permissions to function:

• webRequest: To detect outgoing network calls.
• tabs: To associate requests with the specific tab you are viewing.
• storage: To temporarily hold the list of domains in memory.
• <all_urls>: Required to detect requests to any domain on the internet.

License

MIT License