Multicast Ethernet traffic is not being received
 

I am the owner of a Dell D6000 dock station which, as far as I know, is a DisplayLink device. Everything is working almost perfectly under Ubuntu 18.04, but I was not receiving IPv6 traffic on the dock's Ethernet port.

Upon closer inspection, I have discovered that Ethernet multicast traffic does not reach the computer, only broadcast and unicast traffic does. I have checked this with the wireshark tool. This was the ultimate reason why IPv6 was failing to obtain a valid address.

I have also checked that mDNS, that also depends on proper Ethernet multicast, is not working, as avahi-discover does no show any device, unless I plug the computer to another dock in the same network segment.

I am more than willing to provide any assistance to help to solve this issue.

Best regards,

Bug (and patch) provided
 

This was a problem with linux's cdc_ncm driver. I have filed the corresponding bug at launchpad and also provided a patch that works ok for me.

https://bugs.launchpad.net/ubuntu/+s...x/+bug/1779173

Impressive, thanks! Fingers crossed for getting it upstream!

Regards,
Michal