CODEWITHSUNDEEP
c#.net
Yanshof
Yanshof

Reputation: 9926

Control on the network card that will send UDP message

On my machine i have 2 network card. I need to send 2 udp messages but each of them will be send by different network card.

How can i do it ?

Upvotes: 0

Views: 39

Answers (1)

Martin Liversage
Martin Liversage

Reputation: 106816

You need some way to identify the network interfaces. One way is to use their names:

var networkInterfaceNames = new HashSet<string>() {
  "Local Area Connection",
  "Loopback Pseudo-Interface 1"
};

Then you need to get the local IP addresses of these interfaces. I assume that you want to use IPv4 and that your interfaces have been assigned IPv4 addresses (AddressFamily.InterNetwork):

var localIpAddresses = NetworkInterface
  .GetAllNetworkInterfaces()
  .Where(ni => networkInterfaceNames.Contains(ni.Name))
  .Select(
    ni => ni
      .GetIPProperties()
      .UnicastAddresses
      .First(ua => ua.Address.AddressFamily == AddressFamily.InterNetwork)
  );

Then you need to send UDP packets using these local end points. One way to do that is to use UdpClient:

foreach (var localIpAddress in localIpAddresses) {
  const Int32 LocalPort = 1234;
  var localEndPoint = new IPEndPoint(localIpAddress.Address, LocalPort);
  using (var udpClient = new UdpClient(localEndPoint)) {
    const Int32 RemotePort = 4321;
    var remoteEndPoint = new IPEndPoint(IPAddress.Parse("10.20.30.40"), RemotePort);
    Byte[] payload = ...
    udpClient.Send(payload, payload.Length, remoteEndPoint);
  }
}

Upvotes: 3

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