UDP Multicast does not work as expected [Answered]

I am starting to play around with UDP for some IPC stuff and wrote a simple UDP Multicast application just to have a playground to advance from, but sadly its not going as expected.

First of all: here is the code of the small program https://gist.github.com/cap5lut/ce3bfda6a0997b647a67a20d78d9e189

My expectation was that the writer sends the data and both readers would receive the data, resulting in an output like

writer: sending 5
reader 1: read 5
reader 2: read 5

but that is not the case, only the writer and reader 1 is spitting out stuff.

what am I doing wrong?

Its possible the 2nd reader isnt being scheduled. Async/await isnt necessarily going to provide concurrency. Try using threads or manually created long running tasks

it is already using task.whenall

Thats not necessarily going to start all three tasks

in my case with multiple serialports it does

Async/await is intended for i/o

This code isnt i/o

just added some more logs, seems the 2nd reader is stuck on socket.Bind(new IPEndPoint(IPAddress.Any, MulticastPort));

its throwing System.Net.Sockets.SocketException (10048)

but now i still dont understand how i would make that work

try https://social.msdn.microsoft.com/Forums/en-US/fe830c54-30ab-4ae6-a86a-7c2a9ccd11cf/udpclient-more-than-one-on-the-same-port?forum=ncl

socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true); did the job, thanks for ur help!

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