test local dead port

hello.go

package main

import (
	"fmt"
	"net"
	"os"
)

func main() {
	arguments := os.Args
	if len(arguments) == 1 {
		fmt.Println("Please provide host:port.")
		return
	}

	for i := 49152; i <= 65535; i++ {
		dialTCP(arguments[1], i)
	}

}

func dialTCP(target string, localPort int) {
	CONNECT := target

	dialer := &net.Dialer{
		LocalAddr: &net.TCPAddr{
			//IP:   net.ParseIP("127.0.0.1"),
			Port: localPort,
		},
	}

	c, err := dialer.Dial("tcp", CONNECT)
	if err != nil {
		fmt.Printf("Connect with local port %d fail with error : %v \n", localPort, err)
		return
	}

	fmt.Printf("Connect with local port %d succuss\n", localPort)

	defer c.Close()
}