This project's goal is to create a bridge between a secured network and the outside world in which TCP connections can be made, similar to ngrok.
The original inspiration for the project was simply wanting a self-hosted version of ngrok so that personal data does not have to travel through an unknown server.
The principal behind how node-grok works is very simple, luckily! The server listens for websocket connections using Socket.io. When the server receives a connection, it chooses a random port in the 203XX range and opens a TCP server and echos this information back to the client. Note: The server does not know or care what port the end application is listening on. It is entirely up to the client to forward these connections to the right port once a websocket event has been received.
Simultaneous connections are made possible by making the server generate a random transaction id when it receives a connection on the port it has opened. This transaction id is then managed on the client-side to make sure that all traffic is sent to the appropriate socket that has been opened.
The easiest way to run the server is by entering the server directory and running docker-compose up -d to run the application in the background. It will automatically bind to the ports 8888 and 20300-20399.
To run the client, enter the client directory, install dependencies with yarn install and run the following command yarn run start --server ${IP_OR_DOMAIN_FOR_YOUR_SERVER}:8888 --port ${LOCAL_PORT_FOR_FORWARDING}