SPF - Simplest TCP Proxy

SPF is a powerful and lightweight TCP/UDP proxy designed for security and performance. This beta version (v1.0.1) serves as a straightforward alternative to established tools like rinetd, socat, and Cloudflare Tunnel, facilitating seamless access to home-hosted applications without complex configurations.

Key Features

• Cloudflare Tunnel Alternative: Enable website hosting from home without needing a Cloudflare account, complex port forwarding, or a static IP.
• Simple Commands: Quickly set up communications with commands such as:

  spf relay mysite.com
  spf expose 3000 --relay mysite.com
  

  Your local app becomes accessible at https://myapp.mysite.com.
• Core Functionality: Hosting solutions gain the following capabilities:
  • TCP Port Forwarding for high-performance proxying.
  • Tunnel Mode to expose home servers.
  • Relay Mode to operate a tunnel server on a VPS.
  • TLS Termination using OpenSSL for secure connections.
  • Load Balancing options like round-robin or least connections.
  • Comprehensive Health Checks to proactively detect backend failures.
  • Rate Limiting for both per-IP and global controls.
• Enterprise Security: SPF incorporates advanced security features, such as:
  • Audit Logging providing JSON structured events for monitoring and compliance.
  • IP Blocking with options for manual and automatic settings.
  • Webhook Alerts for integration with audit tools like Slack or Discord.
  • Threat Intelligence and Anomaly Detection for enhanced protection.
• Operational Excellence: Features aimed at ease of use and advanced monitoring include:
  • Prometheus Metrics for observability.
  • Hot Reload feature allowing for changes without service interruptions.
  • Cross-Platform Compatibility supporting Linux, macOS, Windows, and embedded systems like ESP32.

Visual Architecture

SPF operates through a robust architecture accommodating clients, backend services, and security checks to manage traffic dynamically and securely.

Use Case

The primary use case for SPF is hosting a web application from a local network while overcoming ISP restrictions, CGNAT, and dynamic IP issues.
A low-cost VPS can be utilized to establish a secure, outbound tunnel to facilitate user access to local applications.

Command-Line Interface (CLI)

SPF offers a comprehensive CLI to manage connections, configure rules, log activities, and integrate custom security functionalities seamlessly. Here are some functionality examples:

# Basic forwarding example
spf -f 8080:backend.example.com:80

# Secure TLS forwarding
spf -f 443:10.0.0.1:8080 -c cert.pem -k key.pem

With SPF, users gain a reliable tool for managing TCP connections with enterprise-level security features, all while keeping control over their traffic without incurring unnecessary costs or complexities. This makes SPF an ideal solution for developers and administrators seeking an uncomplicated yet powerful networking tool.