c# - Send broadcast message from all network adapters

Question

I have an application that sends broadcast messages and listens for response packets. Below is the code snippet.

m_socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
m_socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1);

m_socket.Bind(new IPEndPoint(IPAddress.Any, 2000));

m_socket.BeginSendTo(
                    buffer, 
                    0, 
                    buffer.Length, 
                    SocketFlags.None,
                    new IPEndPoint(IPAddress.Broadcast, 2000),
                    Callback), 
                    null
                    );

When I run the application the broadcast message was not being sent. On my machine I have three network adapters. One is my local network adapter and other two are VMWare network virtual adapters. When I run my application I can see (using wireshark network capture) that the broadcast message is being sent from one of the VMWare network adapters.

I would like to modify the code so that the broadcast message will be sent from all network adapters on the pc. What is the best way to do that?

Answer 1

You can use the following to get all your IP Addresses (and a lot more). So you can iterate through the list and bind (like Jon B said) to the specific IP you want when you send out your multicast.

foreach (var i in System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces())
    foreach (var ua in i.GetIPProperties().UnicastAddresses)
        Console.WriteLine(ua.Address);