Meshtastic MQTT Broker with Enhanced Security & Privacy

A feature-rich MQTT broker specifically designed for Meshtastic mesh networks with advanced packet filtering, rate limiting, privacy controls, and moderation capabilities.

🚀 Features

Core Security

• Fail2Ban Style Connection Moderation - Automatically ban abusive clients
• Rate Limiting - Per-node and global packet rate limits with duplicate detection
• Topic Filtering - Whitelist/blacklist MQTT topics
• Connection ACLs - Allow/block specific clients

Privacy Controls

• Location Filtering - Block or strip GPS data from POSITION packets
• Position Precision Reduction - Degrade location accuracy for privacy
• Bitfield Stripping - Remove "OK to MQTT" consent metadata
• Selective Node Filtering - Per-node location policies

Packet Modification

• Zero-Hopping - Prevent specific packet types from being forwarded
• Hop Count Limits - Enforce maximum hop counts
• Port Number Filtering - Block/allow specific Meshtastic port numbers

Monitoring

• Real-time Statistics - Track packets, bans, rate limits, and filters
• Comprehensive Logging - Serilog integration with configurable levels
• Metrics Export - Built-in statistics reporting

📋 Requirements

• .NET 9.0 SDK
• Docker (optional, for containerized deployment)

🔧 Quick Start

# Clone the repository
git clone https://github.com/yourusername/meshtastic-mqtt-broker.git
cd meshtastic-mqtt-broker

# Copy and customize configuration
cp appsettings.json appsettings.local.json

# Build and run
dotnet restore
dotnet build
dotnet run

⚙️ Configuration Example

{
  "MqttBroker": {
    "Port": 8883,
    "UseSsl": true
  },
  "RateLimiting": {
    "Enabled": true,
    "PerNodePacketLimit": {
      "MaxPacketsPerMinute": 60
    }
  },
  "LocationFilter": {
    "ReducePositionPrecision": true,
    "TargetPrecisionBits": 12
  },
  "PacketFiltering": {
    "BlockUnknownTopics": true,
    "ZeroHopPortNums": [67]
  }
}

📚 Documentation

• Implementation Guide - Complete setup instructions
• Zero-Hopping Explained - How hop count modification works
• Protobuf Setup Guide - Adding Meshtastic protobuf support
• Bitfield Stripping Guide - Removing "OK to MQTT" flags
• Location Blocking Guide - Privacy controls for GPS data
• Security Flow Diagrams - Visual guide to security features

🎯 Common Use Cases

Maximum Privacy

{
  "LocationFilter": { "BlockPositionPackets": true },
  "PacketModification": { "StripOkToMqttBitfield": true }
}

Public Network

{
  "LocationFilter": {
    "ReducePositionPrecision": true,
    "TargetPrecisionBits": 12
  }
}

Testing/Development

{
  "RateLimiting": { "Enabled": false },
  "PacketFiltering": { "BlockUnknownTopics": false }
}

📊 Status

Working without protobuf:

• ✅ Rate limiting
• ✅ Fail2Ban
• ✅ Topic filtering
• ✅ Connection ACLs

Requires protobuf setup (guide):

• ⏳ Zero-hopping
• ⏳ Location stripping
• ⏳ Bitfield stripping
• ⏳ Precision reduction

📜 License

GPL-3.0 License - See LICENSE file

🙏 Acknowledgments

• Original boilerplate: meshtastic/mqtt
• Meshtastic Project: meshtastic.org
• MQTTnet Library: dotnet/MQTTnet

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Made with ❤️ for the Meshtastic community