Grappl is a tool that lets you host virtually any type of server anywhere, with no port forwarding! People connecting don't have to download anything to connect to Grappl'd servers, unlike with other programs such as LogMeIn Hamachi . All you have to do to run it is run the .jar, choose whether you want to be logged in or anonymous, specify which port your server is bound to, and your server will be open for anyone to connect.

Better yet, it's completely free software, and the client is licensed LGPL v.2.1. How to Run Start Grappl. Log in or choose to be anonymous. Enter your server's local port number. The public address will appear in the Grappl window.