How to do a UDP multicast across the local network in c#?

Question

I am trying to get some simple UDP communication working on my local network.

All i want to do is do a multicast to all machines on the network

Here is my se

Answer 1

I've just spent 4 hours on something similar (I think), the solution for me was:

client.Client.Bind(new IPEndPoint(IPAddress.Any, SSDP_PORT));
client.JoinMulticastGroup(SSDP_IP,IP.ExternalIPAddresses.First());
client.MulticastLoopback = true;

Using a specific (first external) IP address on the multicast group.