NNTP Proxy

A high-performance round-robin NNTP proxy server written in Rust.

Features

• 🔄 Round-robin load balancing - Distributes connections evenly across backend servers
• ⚡ Async/await - Built on Tokio for high concurrency
• 📝 TOML Configuration - Simple and readable configuration format
• 🔍 Structured logging - Detailed logging with tracing
• 🛠️ Nix development environment - Reproducible development setup
• 📊 Connection tracking - Logs client connections and backend routing

Quick Start

Prerequisites

• Nix with flakes enabled
• direnv (optional but recommended)

Development Setup

1. Clone the repository:

git clone <repository-url>
cd nntp-proxy

2. Enter the development environment:

# If using direnv
direnv allow

# Or manually with nix
nix develop

3. Build and run:

cargo build
cargo run

Configuration

The proxy uses a TOML configuration file (config.toml by default):

[[servers]]
host = "news.example.com"
port = 119
name = "Example News Server 1"
# Optional authentication
username = "your_username"
password = "your_password"
# Connection limit (defaults to 10 if not specified)
max_connections = 20

[[servers]]
host = "nntp.example.org"
port = 119
name = "Example News Server 2"
max_connections = 10

[[servers]]
host = "localhost"
port = 1119
name = "Local Test Server"
max_connections = 5

Configuration Fields

• host - Backend server hostname
• port - Backend server port (default: 119)
• name - Friendly name for the server
• username - Optional authentication username
• password - Optional authentication password
• max_connections - Maximum concurrent connections to this server (default: 10)

Usage

# Run with default settings (port 8119, config.toml)
cargo run

# Specify custom port and config
cargo run -- --port 8120 --config my-config.toml

# Show help
cargo run -- --help

Command Line Options

• -p, --port <PORT> - Port to listen on (default: 8119)
• -c, --config <CONFIG> - Configuration file path (default: config.toml)
• -h, --help - Print help information
• -V, --version - Print version information

Testing

To test the proxy, you can use telnet to connect:

# Connect to the proxy
telnet localhost 8119

# The connection will be forwarded to one of the configured backend servers
# in round-robin fashion

How it Works

1. Client Connection: A client connects to the proxy on the configured port
2. Server Selection: The proxy selects the next backend server using round-robin
3. Backend Connection: The proxy establishes a connection to the selected backend
4. Bidirectional Proxy: Data is forwarded in both directions between client and backend
5. Connection Cleanup: When either side closes, both connections are cleaned up

Architecture

The proxy is built with:

• Tokio: Async runtime for handling many concurrent connections
• Tracing: Structured logging for observability
• Clap: Command-line argument parsing
• Serde + TOML: Configuration file handling
• Anyhow: Error handling

Building for Production

# Build optimized release version
cargo build --release

# The binary will be in target/release/nntp-proxy

License

MIT License - see LICENSE file for details.