A small security-focused tool that scans your local network for connected devices, identifies likely manufacturers using MAC address lookups, and highlights unknown/new devices in a simple dashboard output.

Goal: quick visibility into “who is on my network” + basic device attribution for a home / lab environment.

• Smart subnet auto-detection (handles VPNs / virtual adapters)
• Windows-friendly fallback scanning (no Npcap required)
• MAC OUI manufacturer detection
• Strict allowlist mode (security monitoring)
• Device baseline database (detect newly seen devices)
• Gateway role detection (clearly marks network gateway)
• Watch mode (continuous monitoring)
• JSON / NDJSON output for scripting & CI
• Concurrency control (--max-workers)
• Automation-ready exit codes

1. Detects the active network interface + local subnet (example: 192.168.1.0/24)
2. Scans the subnet to find live hosts
3. Resolves IP → MAC
4. Uses the MAC prefix (OUI) to guess the manufacturer
5. Compares scan results against your allowlist / previously seen devices
6. Prints a dashboard view and optionally saves output files

• Python 3.11+ recommended (3.12 works great)
• Fully supported on Windows (Npcap optional for advanced scanning).

git clone https://github.com/<your-username>/sec-network-device-scanner.git
cd sec-network-device-scanner

python -m venv .venv
# Linux/macOS
source .venv/bin/activate
# Windows (PowerShell)
# .\.venv\Scripts\Activate.ps1

pip install -e .

• --strict
• watch
• --json
• --show-nets
• --max-workers

sec-network-device-scanner scan

sec-network-device-scanner scan --out results.json

sec-network-device-scanner scan --allow allowlist.json

{
  "devices": [
    { "mac": "AA:BB:CC:11:22:33", "name": "My Laptop" },
    { "mac": "44:55:66:77:88:99", "name": "Router" }
  ]
}

Role ┃ IP ┃ MAC ┃ Manufacturer ┃ Status ┃ Name           
...

{
  "timestamp_utc": "...",
  "network": "10.175.142.0/24",
  "gateway_ip": "10.175.142.245",
  "counts": {
    "found": 1,
    "new": 0,
    "unknown": 0
  },
  "devices": [...]
}

Designed for scripts/CI and security workflows:

sec-network-device-scanner/
├─ src/sec_network_device_scanner/
│  ├─ __init__.py
│  ├─ cli.py
│  ├─ scanner.py
│  ├─ oui.py
│  └─ storage.py
├─ tests/
├─ .github/workflows/
├─ pyproject.toml
└─ README.md

This tool is meant for networks you own or have permission to test. Results depend on local network visibility (VLANs, client isolation, firewall rules, etc.). Manufacturer detection is best-effort; OUI databases can be incomplete. Some devices may hide MAC addresses or appear behind NAT.