我正在尝试通过 NAT 向客户端发送 udp 数据包,我们都属于不同的 NAT,我们熟悉 STUN 的理论,因此实现此目的的方法是通过“打孔”通过一个简单的 STUN 服务器..
基本上,服务器只返回另一个“已连接”客户端的外部 IP 地址和端口,然后我可以使用它通过 NAT 将数据包发送到客户端......但是,尽管我们设法获取了彼此的外部 IP 和端口。 .我们在发送后仍然无法收到来自对方的任何东西......在搜索论坛和数小时的头颅后,我们仍然无法提出解决方案......想知道是否有熟悉 STUN 的人能够给我们一些关于我们哪里出错的指示或建议......
下面是我们写的小客户...
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.net.SocketException;
import java.net.UnknownHostException;
import javax.swing.JOptionPane;
public class Client {
DatagramSocket socket;
public Client(){
try {
socket = new DatagramSocket();
String data = "Initiate Stun Server";
byte[] receive = data.getBytes();
InetAddress host = InetAddress.getByName("the.stun.server.ipaddress");
DatagramPacket pk = new DatagramPacket(receive,receive.length,host,9345);
socket.send(pk); //send packet to server to initiate udp communication
//spawn a new Thread to listen for any incoming packets
new Thread(){
public void run(){
byte[] r;
DatagramPacket rp;
while(true){
System.out.println("Start listening on new socket");
r = new byte[1024];
rp = new DatagramPacket(r,r.length);
try {
socket.receive(rp);
System.out.println(new String(rp.getData()));
} catch (IOException e) {
e.printStackTrace();
}
}
}
}.start();
String m = JOptionPane.showInputDialog(null,"Enter message to send");
InetAddress connect = InetAddress.getByName(JOptionPane.showInputDialog(null,"Enter address to send message to"));//This is where we input the external ip
int connectPort = Integer.parseInt(JOptionPane.showInputDialog(null,"Enter port of the addressee"));//input port
DatagramPacket p = new DatagramPacket(m.getBytes(),m.getBytes().length,connect,connectPort);
socket.send(p);
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void main(String args[]){
Client c = new Client();
}
}