A fake tcp service for joking...

fake-service.go

package main

import (
	"flag"
	"fmt"
	"log"
	"net"
	"os"
)

var (
	optPort    = flag.String("p", "12345", "config file")
	optLogPath = flag.String("l", "/dev/null", "log path with log name")
	optHelp    = flag.Bool("h", false, "help parameter")
	panicCount = 0
	logfile    *os.File
)

func handleConn(tcpConn *net.TCPConn) {
	if tcpConn == nil {
		return
	}

	tcpConn.Write([]byte("哥们儿,你TM是在逗我么?"))
	tcpConn.Close()
}

//Error handling
func handleError(err error) {
	if err == nil {
		return
	}
	log.Printf("error:%s\n", err.Error())
}

//Print usage
func printUsage() {
	fmt.Println("Fake service v1.0")
	fmt.Println("Usage: ./echo -p 12345 -l ./output.log")
	fmt.Println("-p: Port to listen")
	fmt.Println("-l: Log file path")
	fmt.Println("-h: Show help information")
}

func initLog() {
	logfile, err := os.OpenFile(*optLogPath, os.O_RDWR|os.O_CREATE, 0666)

	if err != nil {
		fmt.Printf("%s\r\n", err.Error())
		os.Exit(-1)
	}

	log.SetOutput(logfile)
}

func main() {
	if len(os.Args) < 2 {
		printUsage()
		return
	}

	flag.Parse()
	if *optHelp {
		printUsage()
		return
	}

	initLog()
	defer logfile.Close()

	tcpAddr, err := net.ResolveTCPAddr("tcp4", "0.0.0.0:"+*optPort)
	handleError(err)

	log.Println("Running... Port listening: " + *optPort)
	tcpListener, err := net.ListenTCP("tcp4", tcpAddr)

	handleError(err)
	defer tcpListener.Close()

	for {
		tcpConn, err := tcpListener.AcceptTCP()
		log.Printf("The client:%s has connected!\n", tcpConn.RemoteAddr().String())
		handleError(err)
		defer tcpConn.Close()
		go handleConn(tcpConn)
	}
}

Please modify
tcpAddr, err := net.ResolveTCPAddr("tcp4", "localhost:"+port)
to
tcpAddr, err := net.ResolveTCPAddr("tcp4", "0.0.0.0:"+port)

@robotJiang Done.