Java DatagramSocket沒有接收到來自某些路由器的UDP廣播

我有一個Android客戶端和純Java服務器都在同一個子網上，並且我正在從客戶端向服務器發送UDP廣播數據包。對於一些路由器（Netgear，Cisco），服務器愉快地接收數據包，但是對於我的華碩路由器，服務器機器接收到數據包，服務器DatagramSocket沒有。Java DatagramSocket沒有接收到來自某些路由器的UDP廣播

NB在任何情況下，Wireshark都會顯示數據包正在到達服務器計算機。但是當使用Asus路由器時，DatagramSocket似乎看不到它們。爲了簡單起見，服務器只有一個到路由器的以太網連接。

代碼非常標準。

客戶：

DatagramSocket socket = null; 
try { 
    socket = new DatagramSocket(); 
    socket.setSoTimeout(500); // 500 millis 

    while (isRunning()) { 
     final InetAddress broadcastAddress = getSubnetBroadcastAddress(); 
     final DatagramPacket outboundPacket = new DatagramPacket(REQUEST_MESSAGE, REQUEST_MESSAGE.length, broadcastAddress, broadcastPort); 
     socket.send(outboundPacket); 
    } 

} catch (IOException e) { 
    Log.i(TAG, "Beacon failed", e); 
} finally { 
    if (socket != null) { 
     socket.close(); 
    } 
} 

private InetAddress getSubnetBroadcastAddress() throws IOException { 
    final WifiManager wifi = (WifiManager) context.getSystemService(Context.WIFI_SERVICE); 
    final DhcpInfo dhcp = wifi.getDhcpInfo(); 
    if (dhcp == null) { 
     // No successful DHCP request. Go with best effort. 
     Log.d(TAG, "#getBroadcastAddress - No DHCP info so using generic broadcast address"); 
     return InetAddress.getByName("255.255.255.255"); 
    } 

    final int broadcast = (dhcp.ipAddress & dhcp.netmask) | ~dhcp.netmask; 
    final byte[] quads = new byte[4]; 
    for (int k = 0; k < 4; k++) { 
     quads[k] = (byte) ((broadcast >> k * 8) & 0xFF); 
    } 
    return InetAddress.getByAddress(quads); 
}

服務器：

DatagramSocket socket = null; 
    try { 
     socket = new DatagramSocket(broadcastPort); 
     socket.setSoTimeout(LISTENING_TIMEOUT); 
     socket.setBroadcast(true); 
     while (keepRunning) { 
      try { 
       final byte[] buffer = new byte[1024]; 
       final DatagramPacket receivedPacket = new DatagramPacket(buffer, buffer.length); 
       socket.receive(receivedPacket); 
       log.debug("Received packet : " + receivedPacket.toString()); 
      } catch (SocketTimeoutException e) { 
       log.debug("#run BeaconRunnable socket timed out"); 
      } 
     } 
    } catch (IOException e) { 
     log.warn("Error while receiving message", e); 
     if (socket != null) { 
      socket.close(); 
     } 
    }

是什麼造成DatagramSocket的不看到華碩路由器的UDP廣播包？

來源

2015-03-31 William

對於後面的那些......

上面的代碼沒有任何問題。路由器配置沒有任何問題。

在Windows防火牆中添加了一條規則，阻止來自公共連接的傳入UDP，並且出於某種原因，Asus路由器被視爲公共連接。

禁用該規則會讓所有的工作都成功。

來源

2015-04-01 11:08:58 William

Java DatagramSocket沒有接收到來自某些路由器的UDP廣播

回答

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