Comment 14 for bug 1480979

What's more annoying is that blocking multicast blocks IPv6 (Neighbour Discovery uses multicast). Libvirt doesn't explicitly document blocking multicast, and definitely doesn't document breaking IPv6.

https://bugzilla.redhat.com/show_bug.cgi?id=1035253#c15

I hope that can be fixed (just allow multicast reception), but in the mean time you might have to document that as well.