On Tue, Feb 04, 2014 at 11:08:09PM +0100, Steinar H. Gunderson wrote:

On Thu, Jan 30, 2014 at 11:44:11PM +0100, Hannes Frederic Sowa wrote:

quoted

The routing lookup is done at IP_ADD_MEMBERSHIP time. I really wonder why you
have routed the 239.0.0.0/8 range to eth0.11. It seems to me that the kernel
does what you told it to do. ;)

multicast flag on ip route is just used for multicast forwarding and does not
matter for local multicast. Also if we find unicast route first (more
specific) kernel does not do backtracking if destination is in multicast
scope.

Hah, you're right. The issue was a combination of:

Thanks for letting me know!

 1. mediatomb's initscript on Debian at some point started to add a bogus
    239.0.0.0/8 route (and I didn't notice this because I earlier tested with
    addresses outside this range).
 2. I didn't properly understand that the multicast flag on the route did not
    matter (although it really should!).

Hmm, maybe that would be good but I am not sure if that could break existing
setups if we change that now. It seems it is handled like that since Alexey
implemented it in that way.

Greetings,

  Hannes