Huginn Net fingerprints TCP, HTTP, and TLS traffic passively. No active probes, no tshark, no wireshark. Pure Rust, built entirely on open-source specifications: p0f v3 for TCP, FoxIO's JA4 for TLS, and the Akamai HTTP/2 fingerprinting spec. All signature databases are open source and community-driven.

What is Passive Traffic Fingerprinting?

Passive fingerprinting infers information about remote hosts without sending any probes. By analyzing TCP/IP packets and TLS handshakes, Huginn Net identifies:

• Operating Systems - Using p0f-inspired TCP fingerprinting to identify OS type, version, and network stack
• Applications & Browsers - Using HTTP headers and JA4 TLS client fingerprinting for precise application identification
• Network Infrastructure - Detecting intermediary devices, proxies, and load balancers
• Client Capabilities - TLS versions, cipher suites, and supported extensions

Network Stack analysis supported by Huginn Net (OSI Model)

Layer	Protocol / Feature	Huginn Net Analysis
7	TLS	JA4 (FoxIO-style) + stable signature
7	HTTP	HTTP/1 & HTTP/2 - Headers, User-Agent, Lang
4	TCP	OS Fingerprinting (p0f-style)

📚 Huginn Net Crates

Crate	Description	Documentation
huginn-net	TCP-HTTP-TLS Analysis - Complete multi-protocol network fingerprinting	📖 Usage Guide
huginn-net-tcp	TCP Analysis - OS fingerprinting, MTU detection, uptime estimation	📖 TCP Guide
huginn-net-http	HTTP Analysis - Browser detection, HTTP/1.x & HTTP/2 fingerprinting	📖 HTTP Guide
huginn-net-tls	TLS Client Analysis - JA4 fingerprinting, TLS version detection	📖 TLS Guide

Which library should I use?

• Multi protocol scanning: Use huginn-net for complete network analysis
• TCP only: Use huginn-net-tcp for OS detection and TCP analysis
• HTTP only: Use huginn-net-http for browser and web server detection
• TLS only: Use huginn-net-tls for JA4 fingerprinting and TLS analysis
• Advanced: Use huginn-net-db directly for custom signature parsing

🚀 Quick Start

Note: Live packet capture requires libpcap (usually pre-installed on Linux/macOS).

Choose Your Approach

For multi-protocol analysis:

[dependencies]
huginn-net = "2.0.0"  # Complete analysis suite

For specific protocols:

[dependencies]
huginn-net-tcp = "2.0.0"   # TCP/OS fingerprinting only
huginn-net-http = "2.0.0"  # HTTP analysis only
huginn-net-tls = "2.0.0"   # TLS/JA4 analysis only
huginn-net-db = { version = "2.0.0", features = ["tcp", "http"] }  # signature matching for TCP/HTTP (not needed for TLS)

Usage & Examples

For detailed usage examples, installation guides, and complete code samples:

📖 Complete Usage Guide - huginn-net module

📚 Examples & Tutorials - Working examples with:

• Live network capture - Real-time analysis
• PCAP file analysis - Offline traffic analysis
• Protocol-specific examples - TCP, HTTP, TLS focused analysis

Performance

Huginn-net is production-ready. It handles millions of packets per second per core, scales with parallel workers, and adds no overhead from parsers or matchers you do not enable.

Unlike p0f and similar tools, single-threaded, monolithic binaries; huginn-net is a modular Rust library with built-in parallel processing. Cargo feature flags eliminate unused parsers at compile time, so you only pay for what you actually use, and a worker pool scales throughput across cores without any extra infrastructure.

See benches/README.md for detailed throughput numbers, 10 Gbps capacity planning, and methodology.

Validated Device Categories

• Desktop Operating Systems - Windows (XP/7/8/10), Linux distributions, macOS
• Mobile Devices - Android devices, iPhone/iPad
• Gaming Consoles - Nintendo 3DS, Nintendo Wii
• Web Browsers - Chrome, Firefox, Safari, Edge, Opera
• Web Servers - Apache, nginx, IIS, lighttpd
• Network Tools - wget, curl, various crawlers and bots
• Legacy Systems - Older Windows versions, Unix variants

Based on signatures available in the p0f database. See huginn-net-db/config/p0f.fp for complete signature list.

Advanced Features

Multi-Protocol Support

• TCP SYN/SYN+ACK fingerprinting for OS detection
• HTTP Request/Response analysis for application identification
• HTTP/2 Akamai fingerprinting extracts SETTINGS, WINDOW_UPDATE, PRIORITY, and pseudo-header order; used by huginn-proxy to inject fingerprints as HTTP headers
• TLS ClientHello analysis with JA4 fingerprinting for client identification, including the stable variant JA4_s1 / JA4_s1r
• MTU Discovery for link type detection
• Uptime Estimation from TCP timestamps (limited accuracy on modern systems)
• Custom Signature Databases - bring your own signatures or contribute to the shared database

Packet Filtering

Optional packet filtering by port and/or IP address for improved performance. Filters are applied before full packet parsing, reducing CPU overhead. Available across all crates. See Examples & Tutorials for usage.

Matching Quality

Each match gets a quality score based on the distance between the observed packet and the closest known signature. A richer database means better scores.

Quality Metrics

• Perfect Match (1.0): Exact signature match with zero distance
• High Quality (0.8-0.95): Very close match with minimal differences
• Medium Quality (0.6-0.8): Good match with some variations
• Low Quality (0.4-0.6): Acceptable match but with notable differences
• Poor Quality (<0.4): Weak match, use with caution

Companion: huginn-proxy

huginn-proxy: High-performance reverse proxy forwarding TLS (JA4), HTTP/2 (Akamai), and TCP-SYN (eBPF-powered) fingerprints as HTTP headers.

Routes incoming connections to backend services while passively extracting TLS (JA4), HTTP/2 (Akamai), and TCP SYN (p0f-style) fingerprints and injecting them as headers. TCP SYN fingerprinting runs via an XDP/TC eBPF program.

🤝 Contributing

We welcome contributions! Please see our Contributing Guide for detailed information on how to get started.

Next Milestones

• Enhanced Database - Continuous signature updates and community contributions
• Advanced Analytics - Pattern analysis and reporting tools
• Real-time Streaming - High-performance packet processing pipelines

📄 License

Dual-licensed under MIT or Apache 2.0.

Attribution

huginn-net is an independent Rust implementation inspired by the methodologies of p0f and JA4.

• p0f v3 (spec): TCP SYN fingerprinting follows the p0f v3 specification by Michal Zalewski.
• JA4 (spec): TLS fingerprinting follows the JA4 specification by FoxIO, LLC (BSD 3-Clause). Written from scratch; no JA4+ components (FoxIO License 1.1) are included. Copyright (c) 2023, FoxIO, LLC.
• Akamai HTTP/2 (spec): HTTP/2 fingerprinting follows the Blackhat EU 2017 specification.