Why doesn't a remote client connect to a simple golang server running locally?

Question

go

Here is a simple server on th

package main

import (
  "bufio"
  "fmt"
  "log"
  "net"
)

// Our server
const (
  HOST = ""
  PORT = "8080"
  TYPE = "tcp4"
)

func main() {

  listener, err := net.Listen(TYPE, fmt.Sprintf("%s:%s", HOST, PORT))
  if err != nil {
    log.Fatal("Error listening " + err.Error())
  }

  defer func() {
    if err := listener.Close(); err != nil {
      fmt.Println("Error stoping listener")
      fmt.Println("Listener closed.")
    }
  }()

  fmt.Printf("[+] Server listening on %s:%s type %s\n", HOST, PORT, TYPE)

  for {

    connection, err := listener.Accept()
    if err != nil {
      fmt.Println("Error accepting connection ", err.Error())
      continue
    }

    fmt.Println("Accepted connection: ", connection.RemoteAddr().String())

    go handleRequest(connection)

  }

}

func handleRequest(connection net.Conn) error {

  defer func() {
    if err := connection.Close(); err != nil {
      fmt.Println("Error closing connection: ", err.Error())
    }
  }()

  r := bufio.NewReader(connection)
  w := bufio.NewWriter(connection)
  scanr := bufio.NewScanner(r)

  for {
    scanned := scanr.Scan()

    if !scanned {
      if err := scanr.Err(); err != nil {
        log.Printf("Scanning error on %v(%v)", err, connection.RemoteAddr().String())
        return err
      }
    }

    text := scanr.Text()
    fmt.Printf("Recieved data from %s: %s\n", connection.RemoteAddr().String(), text)
    w.WriteString(text + "\r\n")
    w.Flush()

    if text == "quit" || text == "exit" {
      fmt.Println("Recieved exit request", connection.RemoteAddr().String(), text)
      break
    }
  }

  return nil

}

I look locally at my ip address: 192.168.31.245 I start the
virtual machine and in it through telnet 192.168.31.245 8080 I get this command to connect, everything is ok.
In the same way, I try to connect to a remote server dedicated to centos and constantly writes "Trying 192.168.31.243 ..." but the connection itself does not go ..
What could be the problem?

Answer 1

192.168.31.245 is a local IP address, but you need an external IP address.
You can use ngrok