I started writing a TCP tproxy library for golang at: https://github.com/elico/go-linux-tproxy It works pretty well and there is an example for a simple TCP proxy which just peeks a bit into the beginning of the connection and then connects the client and the server. The example server was written for http and there for would require the connection to be a Client sends data first state. Later I will maybe provide an example which will test for both client and server connections for data and then decide on what to do. Eliezer