Porthole - Local Port Sharing has been released on Steam.

The tool is a lightweight desktop utility that lets Steam friends access local network ports remotely without port forwarding or public IP exposure - an alternative to VPN services like Hamachi. Porthole is completely free to use.

It’s built for hosting local multiplayer or LAN-only games with distant friends over the internet, without touching router settings.

A lightweight desktop utility that enables Steam friends to access local network ports remotely without port forwarding or public IP exposure. It functions as an alternative to traditional VPN services like Hamachi.

• Supports both TCP and UDP port sharing
• Built-in port detection for running applications
• Works behind NAT and CGNAT without router configuration
• Join via share code or Steam friends list
• Optional password protection for lobbies
• Per-port approval and host controls
• Peer-to-peer or Valve relay routing
• Native GUI and command-line interface
• Cross-platform (Windows and Linux/SteamOS)

Source: Steam