multicast dgram on non-default interface #3232

sixtus opened this Issue May 7, 2012 · 4 comments


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sixtus commented May 7, 2012

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.


  • dgram.send() can not determine the interface itself (as multicast can happen on any interface)
  • passing an address to bind() makes dgram stop hearing its own multicast messages

bnoordhuis commented May 7, 2012

Duly noted. I'll take patches or test cases, preferably both. :-)

sixtus commented May 8, 2012

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:


bnoordhuis commented May 20, 2012

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.


bnoordhuis commented Oct 28, 2013

No follow-up, closing.

bnoordhuis closed this Oct 28, 2013

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