Re: Simple multicast question

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Mon, 23 Nov 2009 11:40:45 -0500
    From:        Greg Troxel <gdt%ir.bbn.com@localhost>
    Message-ID:  <rmiiqd16voy.fsf%fnord.ir.bbn.com@localhost>

  | This seems bizarre to me.  bind sets the source address, which is a
  | separate issue.

It also sets a filter on incoming packets - only those addressed to the
bound address will be received (this is just obvious for TCP, which is
always bound once connected, but for UDP, it is less blatant, but the
same effect exists).

Note it isn't just multicast this applies to, but everything.

Since multicast addresses can't be source addresses, the source addr
setting part of bind is irrelevant there, and you're left with just the
incoming packet filter.

  | 'netstat -ai' should be useful.  but on a netbsd-5 box it isn't showing
  | OSPF groups joined even though ospf (quagga) is running fine.

Try ifmcstat

kre