UDP Multicast MAC not correct? about ethercard HOT 5 OPEN

To receive multicast on the Arduino you need to call enableMulticast():

However, your problem seems to be sending from the Arduino, right?

from ethercard.

Correct

from ethercard.

I'd say give enableMulticast() a try anyway. I'm not sure sending multicast packets is implemented though.

from ethercard.

I have just done a test using socat on my Mac:

echo "Hello World" | socat -u - udp-datagram:225.1.2.1:1234

And can see the packets going to 01:00:5e:01:02:01 using Wireshark.

The code that sets the MAC address for broadcast/multicast addresses is here:
https://github.com/njh/EtherCard/blob/master/src/tcpip.cpp#L384

So it indeed just sets it to FF:FF:FF:FF:FF:FF.
I am a big fan of multicast, so would like to see this working.
I am surprised that your network switch cares - what sort of switch do you have?

I have a very old Ethernet hub that I sometimes use for testing Ethercard - because it blindly copies all packets to all ports, making it easier to diagnose what is going on.

from ethercard.

I am surprised that your network switch cares - what sort of switch do you have?

I am using a Netgear GS108, with nothing more than my PC and the arduino board connected to it. I have tried sending packets over my main network but no results so far.

I did try hardcoding the correct multicast MAC (01:00:5e:01:02:01) as the destination mac, but the packets didn't show up in Wireshark.

from ethercard.