simple TCP proxies

By connecting a client and server’s input and output together, it is possible to create a simple TCP proxy.

Unix

1. Create a named pipe by using the mkfifo command:

mkfifo backpipe

2. Create a server on port 8000 and feed it’s output into a connection to the destination host on port 80 while using the backpipe to feed the host connection’s output back to the server’s input stream:

pync -l 8000 < backpipe | pync host.example.com 80 > backpipe

Python

import pync


def main():
    server = pync.Netcat(port=8000,
        l=True,
        stdin=pync.PIPE,
        stdout=pync.PIPE,
    )
    server.start_process(daemon=True)

    client = pync.Netcat('host.example.com', 80,
        stdin=server.stdout,
        stdout=server.stdin,
    )
    client.run()


if __name__ == '__main__':
    main()