Simple Network Sniffer

Android Wi-Fi Network Scanner App

Simple Network Sniffer is a lightweight Android app designed to scan the local Wi-Fi subnet for active and reachable devices. It demonstrates basic network discovery using Java and the Android SDK, and was originally built for educational purposes.

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📈 What It Does

• Retrieves the device's current Wi-Fi IP address and subnet
• Iterates through the IP range (e.g., 192.168.1.1 to 192.168.1.254)
• Attempts to connect to each IP using InetAddress.isReachable
• Logs reachable hosts and their canonical names to Logcat

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👩‍💻 Use Cases

• Understand how subnet scanning works in Android apps
• Demonstrate AsyncTask and background threading
• Show how to use WifiManager and ConnectivityManager to access network info

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🧰 Tech Stack

• Java (Android)
• Android SDK (pre-AndroidX)
• AsyncTask for background scanning
• WifiManager, ConnectivityManager, InetAddress for network operations

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✨ Getting Started

Prerequisites

• Android Studio (3.x+)
• Android SDK (API 23–28 recommended)
• Java 8

Build & Run

1. Clone the repo:

   git clone https://github.com/didiergarcia/simple-network-sniffer.git
   cd simple-network-sniffer

2. Open in Android Studio.
3. Build and run on a real device (not emulator) connected to Wi-Fi.

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🧪 How to Use

1. Launch the app
2. Tap the "Sniff" button
3. Watch Logcat for output showing reachable devices on your subnet

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📊 Example Log Output

Host: router.local [router.local] (192.168.1.1) is reachable!
Host: macbook-pro [macbook-pro] (192.168.1.45) is reachable!

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⚒ Future Improvements

• Use Kotlin and AndroidX libraries
• Add UI to display scan results
• Add hostname resolution timeout settings
• Implement concurrent pinging for faster results

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📄 License

MIT © Didier Garcia
Built for educational and diagnostic purposes.