multicast dgrams really get confused once there are multiple interfaces involved and even worse, when trying to send multicast messages on the non-default interface.
it's so bad, I can't even give you a matrix of what combination leads to what result, but it's a weird combination of not hearing anything, sending on the wrong interface, and receiving on the wrong interface.
Duly noted. I'll take patches or test cases, preferably both. :-)
A test case is really hard to write, as you need to set up networking correctly.
Instead, I tried to demo the strange behavior in this gist: https://gist.github.com/2633625
Thanks, I think I see what you mean. I don't think it's a bug in node or libuv, though. I suspect that you'd see the same behavior with a program written in pure C.
No follow-up, closing.