Can you look on the adjacent multicast router(s) and see if your host is
listed as a group member?  Or is this done with just a flat IP network
(one subnet)?

On Mon, 2004-01-05 at 21:21, Martin Knoblauch wrote:
> --- David Stevens <dlstevens@us.ibm.com> wrote:
> > 
> >
> Hi David,
>  
> > 
> > 
> > Martin,
> >       If you have other hosts on that network that have sent IGMP
> > reports,
> > then
> > the reporter flag will be cleared-- only one member on a network
> > needs to
> > send
> > reports. That doesn't prevent the host from receiving multicasts--
> > presence
> > in
> > /proc/net/igmp indicates it did join the group.
> 
> OK. I just wondered, because all hosts running the 2.4.20-18.7smp
> kernel (RH7.3 errata) show the "1" in the reporter field, while all
> hosts running 2.4.22/2.4.23 (vanilla plus NFS fixes from Trond) show
> "0".
> 
> >       Please send me some details about your set-up and I may be able
> > to
> > help.
> 
>  We are running 21 HP/DL380G3.Each has two internal Broadcom NICs. The
> second one (eth1) is used for the Ganglia multicast.
> 
>  The kernels are 2.4.22 and 2.4.23 (now .24) with some NFS patches. In
> the case of 2.4.24 those are:
> 
> 01-posix_race
> 02-fix_commit
> 03-fix_osx
> 04-fix_lockd3
> 06-fix_unlink
> 07_seekdir
> 
>  from http://www.fys.uio.no/~trondmy/src/Linux-2.4.x/2.4.23-rc1 None of
> those looks like it does something to multicasts. In the worst case I
> could try to run with plain 2.4.22/23, but that would have to ait until
> Wednesday.
> 
>  The kernel-config file is included.
> 
> >       First, are the sender and receiver on the same network, or are
> > you
> > using a multicast router?
> 
>  No. All systems are on the same network.
> 
> >       Second, can you send me a tcpdump-format packet trace
> > (preferrably
> > only the multicast traffic, and as small as you can make it)?
> 
>  What exactely do you want to see? On which box should I run tcpdump?
> Which options (I'm not that deep into network debugging :-)?
> 
> 
> >       You mentioned tg3-- have you tried this with other hardware
> > that
> > worked?
> >
> 
>  The tg3 works with the 2.4.20-18.7smp (and earlier) kernels. It just
> does not work with 2.4.22/23 (did not check 2.4.21). 
> 
>  Unfortunatelly I have no other boxes to test with. I only can say that
> Ganglia never failed in this particular way on any setup.
> 
> Thanks
> Martin
> 
> =====
> ------------------------------------------------------
> Martin Knoblauch
> email: k n o b i AT knobisoft DOT de
> www:   http://www.knobisoft.de
-- 
    Lawrence MacIntyre     865.574.8696     lpz@ornl.gov
               Oak Ridge National Laboratory
High Performance Information Infrastructure Technology Group