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I'm trying to implement a "dynamic" proxy forward to access localhost from Internet, like Ngrok in pure Java.

This guy does essentially the same thing: https://serveo.net/#intro (but, without a client)

The idea would be to use the SAME port on the server, and make a dynamic proxy for each client, based on a subdomain

The problem is that the default implementation throws error on the second connection .. saying that the port is already open.

org.apache.sshd.common.forward.DefaultForwardingFilter # doBind

Who has an idea of how to implement this? The advantage of this is that you do not even need a CLIENT like Ngrok for that ... just using normal ssh would be possible.

ssh -R http2:9000:localhost:8002 localhost -p 4440
ssh -R http2:pSERVER:localhost:pLOCAL localhost -p SSHD_PORT

an option I imagined, is to generate the ports dynamically on the server: IGNORING THE 'pSERVER' port, and creating an HttpProxy, to do the redirection for each port. But I find this very inefficient, I believe it would be possible to do only by analyzing the request header and making the redirects for the corresponding channels / connections

Ricardo Jl Rufino
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1 Answers1

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After too much headache. The code is in very low quality, just a proof of concept that can be implemented.

The implemented idea was made by changing sshd-netty, and adding a function to unpack the http request and remove the HOST HEADER (this needs to be improved here).

Only 1 port on the server is used, and it is kind of a reverse proxy for clients ...

I would like the help of the developers to improve the code in question. My knowledge in Netty and Mina is very limited.

Appreciate:
Source: https://github.com/ricardojlrufino/sshd-dyn-tunneling

Testing: Open 2 connections: 

ssh -v -R http1:9000:localhost:8001 localhost -p 4440   
ssh -v -R http2:9000:localhost:8002 localhost -p 4440

Make requests: 

curl -v -H "Host: http1" http1:9000  
curl -v -H "Host: http2" http2:9000

Start test servers: https://github.com/ricardojlrufino/sshd-dyn-tunneling/blob/tunel/src/test/resources/setup_remotes.sh

Ricardo Jl Rufino
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