NetSynth

Turn network traffic into ambient sound.

NetSynth captures live network traffic (or reads pcap files), classifies packets by protocol, and synthesizes an ambient MP3 soundscape where each traffic type produces a distinct harmonic drone. A ping sounds different from HTTPS noise, which sounds different from a port scan.

Run it, let it listen, press Ctrl+C, get an audio fingerprint of your network.

Quick Start

# Live capture on eth0 (requires root or CAP_NET_RAW)
sudo netsynth -i eth0

# Press Ctrl+C after a few seconds → saves netsynth-<timestamp>.mp3

# Sonify a pcap file (no privileges needed)
netsynth --read capture.pcap -o output.mp3

# Filter to DNS traffic only
sudo netsynth -i eth0 --filter "port 53" -o dns.mp3

Installation

Prerequisites

• Go 1.24+
• C compiler (GCC or Clang) — required for MP3 encoding (CGo)

Build from Source

git clone https://codeberg.org/gurix/yoloyolo.git
cd yoloyolo
go build -o netsynth ./cmd/netsynth

For a smaller binary:

go build -ldflags="-s -w" -o netsynth ./cmd/netsynth

Privileges

Live packet capture requires elevated privileges on Linux:

# Option A: run as root
sudo ./netsynth -i eth0

# Option B: grant capability (preferred)
sudo setcap cap_net_raw=eip ./netsynth
./netsynth -i eth0

Usage

netsynth [flags]

Flag	Description
-i, --interface	Network interface to capture on
--read	Read packets from a pcap file instead of live capture
-o, --output	Output MP3 file path (default: netsynth-<timestamp>.mp3)
--filter	BPF filter expression, tcpdump syntax (e.g. "port 53")
--verbose	Print per-window protocol activity to stderr
--list-interfaces	List available network interfaces and exit

Examples

# Capture all traffic, verbose per-window output
sudo netsynth -i wlan0 --verbose

# Only HTTPS traffic
sudo netsynth -i eth0 --filter "tcp port 443" -o https.mp3

# Sonify a Wireshark capture (output derived: capture.pcap -> capture.mp3)
netsynth --read capture.pcap

# Filter a pcap file to UDP only
netsynth --read traffic.pcap --filter "udp" -o udp-only.mp3

How It Works

NetSynth processes traffic through a four-stage pipeline:

Capture -> Classify -> Aggregate -> Synthesize -> MP3

1. Capture — Packets are read from a live interface (via go-pcap) or a pcap file. Optional BPF filtering reduces the stream to traffic of interest.

2. Classify — Each packet is matched against 12 protocol rules (ICMP, DNS, HTTPS, SSH, HTTP, SMTP, NTP, DHCP, etc.). Unrecognized traffic is deterministically hash-bucketed into 4 "unknown" classes so it still produces distinct sounds.

3. Aggregate — Classified packets are grouped into 500ms time windows. Each window records per-protocol packet counts that drive synthesis amplitudes.

4. Synthesize & Encode — Each traffic class maps to a sine oscillator at a specific frequency and stereo position. Amplitudes rise and fall via EMA smoothing based on traffic volume. All layers are mixed and encoded to MP3 via LAME.

Sound Design

Traffic Class	Frequency Range	Character
ICMP (Ping)	High register	Bright, distinctive ping tone
DNS	Mid-high	Quick lookup sound
HTTPS/TLS	Low register	Deep, steady drone (bulk traffic)
SSH	Mid register	Distinct interactive tone
HTTP	Low-mid	Warm web traffic hum
Unknown 1-4	Dissonant	Eerie, attention-grabbing

Sustained traffic sounds louder; quiet periods fade to silence. The result is a unique audio fingerprint of your network activity.

Project Structure

cmd/netsynth/   CLI entry point (Cobra)
capture/        Packet capture, BPF validation, pcap file reading
classify/       Protocol classification rules and types
aggregate/      Time-window aggregation and summary output
synth/          Oscillators, EMA layers, stereo mixer, tone bank
encode/         MP3 encoding via embedded LAME

Dependencies

Library	Purpose
gopacket/gopacket	Packet decoding
packetcap/go-pcap	Pure Go live capture (no libpcap)
sjzar/go-lame	MP3 encoding (embedded LAME C source)
spf13/cobra	CLI framework

No runtime dependencies beyond the compiled binary. CGo is required at build time only (for LAME).

Testing

go test ./... -v

All tests run without root privileges (capture tests use mock data and programmatically generated pcap files).

License

See LICENSE for details.