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Simple GO TCP proxy
// can be run in go 1.0.3
// build : go build netfwd.go
package main
import (
func main() {
if len(os.Args) != 3 {
fatal("usage: netfwd localIp:localPort remoteIp:remotePort")
localAddr := os.Args[1]
remoteAddr := os.Args[2]
local, err := net.Listen("tcp", localAddr)
if local == nil {
fatal("cannot listen: %v", err)
for {
conn, err := local.Accept()
if conn == nil {
fatal("accept failed: %v", err)
go forward(conn, remoteAddr)
func forward(local net.Conn, remoteAddr string) {
remote, err := net.Dial("tcp",remoteAddr)
if remote == nil {
fmt.Fprintf(os.Stderr, "remote dial failed: %v\n", err)
go io.Copy(local, remote)
go io.Copy(remote, local)
func fatal(s string, a ... interface{}) {
fmt.Fprintf(os.Stderr, "netfwd: %s\n", fmt.Sprintf(s, a))
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    go io.Copy(local, remote) 
    go io.Copy(remote, local) 

key point

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