Java客户端/服务器套接字问题

Question

I am having some issues connecting a client and server together. The client just times out trying to reach the server.

I have already done the following troubleshooting on my network:

• I have port forwarded the ports correctly (I have done so many many times before) and it still times out.
  • I am using a new modem, a ARRIS TG862 and the first one I got was bad, it would not open the ports at all.
  • Now the ports are opening up correctly because I am hosting a website and people can connect, and also I have hosted a few games and there has been no issues.
• The modem I am using is using IPv6 which I do not know if that is an issue or not?
• I have tried different ports and it still does the same thing. I did even revert to my old modem and router combination and it still will not work.

I am out of options and have no idea what is going on.

• The server/client works fine on localhost but as soon as I try to connect externally it fails.
• When the server is running I can go to canyouseeme.org and it can see the opened port and my program exits because something connected to it.
• I am using the same computer to connect and host, which I have done before and it worked fine a long time ago.
• I also tried using different computers to connect to each other (on the same network).

If there is any suggestions on where to start to determine the cause of my problems that would be great, I am just kind of lost on where to diagnose from here. The code is below. I'll even retry some steps if anyone thinks it is something that I already tested.

Client

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.EventListener;


public class Client{
    private static Socket socket;
    private static PrintWriter printWriter;
    private int portNumber = 1337;
    private String hostName = "234.123.1.234";//Not real IP, made up ip address to demonstrate code to stack overflow users


    public static void main(String[] args){
        new Client().validateSecurity();
    }

    public void validateSecurity(String key){
        try {
            Socket kkSocket = new Socket(hostName, portNumber);
            PrintWriter out = new PrintWriter(kkSocket.getOutputStream(), true);
            BufferedReader in = new BufferedReader(
                    new InputStreamReader(kkSocket.getInputStream()));
        }catch(Exception e){

        }
    }
}

Server

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.io.PrintWriter; 
import java.net.ServerSocket; 
import java.net.Socket; 
import java.net.UnknownHostException; 
import java.util.EventListener;

import javax.swing.JFrame;
import javax.swing.JOptionPane;


public class Server{
    private static Socket socket;
    private static PrintWriter printWriter;
    private int portNumber = 1337;


    public static void main(String[] args){
        new Server().validateSecurity("hi");
    }

    public void validateSecurity(String key){
        try
        {
            ServerSocket serverSocket = new ServerSocket(portNumber);
            System.out.println("WAITING ON CONNECTION");
            Socket clientSocket = serverSocket.accept();
            System.out.println("CONNECTION ACCEPTED");
            PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
            BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}

Answer 1

连接超时几乎总是表示防火墙有问题。