如何检查UPnP端口1900和Bonjour端口5353是否被防火墙阻止

发布于 2024-11-10 09:05:02 字数 1110 浏览 3 评论 0原文

我列出了在 C# .NET 中使用 UPnP 的所有局域网设备，我在 C# .NET 中使用 Windows 提供的 UPnP API（通过添加对 UPnP COM 库的引用）。当 UPnP 扫描没有看到任何设备时，我必须检查该端口 (1900) 是否被防火墙阻止，如果是，我必须通知用户。

扫描 UPnP 设备的代码

UPnPDeviceFinder devFinder = new UPnPDeviceFinder();
UPnPDevices devices = devFinder.FindByType("upnp:rootdevice", 0);
Debug.WriteLine("Devices Count:=" + devices.Count);

我已在 LAN 中连接了多个设备，并且我能够在 UPnP 扫描中看到这些设备。当我阻止 1900 端口时 devFinder.FindByType("upnp:rootdevice", 0);返回 0 个设备。所以我需要编写一些端口扫描代码来告诉我端口是打开还是关闭。由于 UPnP 使用 UDP，当我尝试连接到“239.255.255.250:1900”地址时，我没有收到任何异常。下面是我编写的代码片段

try
{
  Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
  IPEndPoint iep = new IPEndPoint(IPAddress.Parse("239.255.255.250"), 1900);

  byte[] data = Encoding.ASCII.GetBytes("This is a test message");
  server.SendTo(data, iep);
  server.Close();
  Console.WriteLine("UPnP Port is open");
}
catch(SocketException ex)
{
  Console.WriteLine("UPnP Port is blocked by firewall");
}

，我在防火墙中阻止了 1900 端口，所以我期待 SocketException，但我从未得到任何异常，所以我无法找到端口是打开还是被阻止

原文

I am listing the all the local area network devices using UPnP in C# .NET, I am using UPnP API's given by windows in C# .NET (by adding reference to UPnP COM Library). When UPnP Scan don't see any device then I have to check whether that port (1900) is blocked by the firewall, if yes I have to notify the user.

Code to scan the UPnP Devices

UPnPDeviceFinder devFinder = new UPnPDeviceFinder();
UPnPDevices devices = devFinder.FindByType("upnp:rootdevice", 0);
Debug.WriteLine("Devices Count:=" + devices.Count);

I have connected multiple devices in the LAN and I am able to see those devices in the UPnP Scan. When I block 1900 port then devFinder.FindByType("upnp:rootdevice", 0); returns 0 devices. So I need to write some port scanning code which will tell me whether the port is open or close. As UPnP use UDP I am not getting any exception when I am trying to connect to the "239.255.255.250:1900" address.
Below is the code snip which I have written

try
{
  Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
  IPEndPoint iep = new IPEndPoint(IPAddress.Parse("239.255.255.250"), 1900);

  byte[] data = Encoding.ASCII.GetBytes("This is a test message");
  server.SendTo(data, iep);
  server.Close();
  Console.WriteLine("UPnP Port is open");
}
catch(SocketException ex)
{
  Console.WriteLine("UPnP Port is blocked by firewall");
}

I have blocked the 1900 port in firewall, so I was expecting the SocketException, but I never gets any exception, so I was not able to find whether port is open or blocked

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