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netcat 와 Back pipe 를 이용한 프록시 서버 구축하기
Proxying
Another useful behaviour is using netcat as a proxy. Both ports and hosts can be redirected. Look at this example:
nc -l 12345 | nc www.google.com 80
Port 12345 represents the request
This starts a nc server on port 12345 and all the connections get redirected to google.com:80. If a web browser makes a request to nc, the request will be sent to google but the response will not be sent to the web browser. That is because pipes are undirectional. This can be worked around with a named pipe to redirect the input and output.
mkfifo backpipe nc -l 12345 0<backpipe | nc www.google.com 80 1>backpipe
