spectraNET

spectraNET is a free per-application network monitor for macOS, Windows and Linux. It measures every connection of every program and shows which apps use the network, how much, with whom, and whether anything looks suspicious, as an animated 2.5D city or a 2D map.

Main features:

• Per-app traffic read from the kernel's own counters, not guessed from sniffed packets
• Hostname of every destination, learned without decrypting anything
• Recognises video, music, calls, web, downloads and games, with TLS version and JA4 fingerprint
• Alerts for malicious or anonymising servers (Feodo Tracker, Spamhaus DROP, Tor exits), unencrypted traffic and first connections to new destinations
• Pause, end or block an app's network access, with an audit log
• 7 and 30-day history per app via the snetd service, Prometheus metrics on request
• Recognises software-defined radio apps (SDR++, GQRX, rtl_tcp, SatDump, dump1090)
• snet command line: top, list, inspect, stream, with man pages and JSON output

Everything is measured and stored locally.