c# – UPnP组播：M-SEARCH(发现)中缺少答案

我已经在iOS环境中测试了相同的代码(在Mac上使用的是iPhone的iPhone模拟器上的Monotouch).它运行正常,我得到我的UPnP设备的所有搜索响应.我也可以从我的Windows程序中看到M-SEARCH消息.

看起来像Windows(或防火墙？)正在隐藏搜索响应.任何想法？

这是代码：

IPEndPoint LocalEndPoint = new IPEndPoint(IPAddress.Any,1900);
IPEndPoint MulticastEndPoint = new IPEndPoint(IPAddress.Parse("239.255.255.250"),1900);

Socket UdpSocket = new Socket(AddressFamily.InterNetwork,SocketType.Dgram,ProtocolType.Udp);

UdpSocket.SetSocketOption(SocketOptionLevel.Socket,SocketOptionName.ReuseAddress,true);
UdpSocket.Bind(LocalEndPoint);
UdpSocket.SetSocketOption(SocketOptionLevel.IP,SocketOptionName.AddMembership,new MulticastOption(MulticastEndPoint.Address,IPAddress.Any));
UdpSocket.SetSocketOption(SocketOptionLevel.IP,SocketOptionName.MulticastTimeToLive,2);
UdpSocket.SetSocketOption(SocketOptionLevel.IP,SocketOptionName.MulticastLoopback,true);

Console.WriteLine("UDP-Socket setup done...rn");

string SearchString = "M-SEARCH * HTTP/1.1rnHOST:239.255.255.250:1900rnMAN:"ssdp:discover"rnST:ssdp:allrnMX:3rnrn";

UdpSocket.SendTo(Encoding.UTF8.GetBytes(SearchString),SocketFlags.None,MulticastEndPoint);

Console.WriteLine("M-Search sent...rn");

byte[] ReceiveBuffer = new byte[64000];

int ReceivedBytes = 0;

while (true)
{
    if (UdpSocket.Available > 0)
    {
        ReceivedBytes = UdpSocket.Receive(ReceiveBuffer,SocketFlags.None);

        if (ReceivedBytes > 0)
        {
            Console.WriteLine(Encoding.UTF8.GetString(ReceiveBuffer,ReceivedBytes));
        }
    }
}