netwatch

Local network scanner and host inventory tool implemented with the Python standard library.

Features

• Discover live hosts within a CIDR block, single IP, or explicit range.
• ICMP ping first with graceful TCP connect fallback when ping is unavailable.
• Optional probing of common ports (default: 22, 80, 443, 3389, 8080) or a custom list.
• Concurrent scanning using worker threads for speed.
• Human-readable table output and optional JSON report generation.

Installation

No external dependencies are required. Use Python 3.10+.

Usage

python netwatch.py 192.168.1.0/24
python netwatch.py 192.168.1.1-192.168.1.50 --ports 22,80,443 --timeout 1.5
python netwatch.py 192.168.1.0/28 --summary --json results.json

Arguments

• CIDR_OR_RANGE (positional): Target CIDR, range, or single IP.
• --ports 22,80,443: Comma-separated list of ports to scan (default common set).
• --timeout SECONDS: Socket timeout for probes (default: 1.0).
• --workers N: Number of concurrent worker threads (default: CPU count).
• --json PATH: Write JSON report to the provided path.
• --summary: Print a condensed summary instead of full details.

Exit Codes

• 0: Success.
• 1: Invalid arguments.
• 2: Runtime error.

Development

Run the test suite with:

python -m unittest