Multicast and IP-conntrack problem

Multicast and IP-conntrack problem

[Michel Wilson]

Hi!

I'm having some problems with ip-connection tracking and multicast packets:
the conntrack stuff doesn't seem to be able to handle multicast packets,
flooding my logs with messages like these:

Feb 28 15:53:00 procyon kernel: NAT: 0 dropping untracked packet c7105b00 1
195.38.203.147 -> 224.0.0.2
Feb 28 15:53:23 procyon kernel: NAT: 0 dropping untracked packet c7a13740 1
195.38.207.229 -> 224.0.0.2
Feb 28 15:53:26 procyon kernel: NAT: 0 dropping untracked packet c7a13740 1
195.38.207.229 -> 224.0.0.2
Feb 28 15:53:31 procyon kernel: NAT: 0 dropping untracked packet c6535a80 1
195.38.207.229 -> 224.0.0.2
Feb 28 15:54:18 procyon kernel: NAT: 0 dropping untracked packet c7a132c0 1
195.38.202.44 -> 224.0.0.2
Feb 28 15:54:21 procyon kernel: NAT: 0 dropping untracked packet c7a132c0 1
195.38.202.44 -> 224.0.0.2
(this is an old logfile, i disabled logging for these messages, because it
generated several megs each day)

I'm currently using kernel 2.4.0-test9, but a friend of mine is using 2.4.0
and is experiencing the same problem.

Is this a known problem which can't be fixed, or is it fixable? And am i
asking this question in the right place here?

Thanks for any help,

Michel Wilson
<michel@procyon14.yi.org>
<mwilson@dds.nl>

Re: Multicast and IP-conntrack problem

[Rusty Russell]

In message <NEBBLEJBILPLHPBNEEHIEEMCCAAA.mwilson@dds.nl> you write:
> Hi!
> 
> I'm having some problems with ip-connection tracking and multicast packets:
> the conntrack stuff doesn't seem to be able to handle multicast packets,
> flooding my logs with messages like these:
> 
> Feb 28 15:53:00 procyon kernel: NAT: 0 dropping untracked packet c7105b00 1
> 195.38.203.147 -> 224.0.0.2

Yes.  Connection tracking doesn't handle multicast.  NAT drops packets
not handled by connection tracking.

Making connection tracking handle multicast is a minor project in itself.

Rusty.
--
Premature optmztion is rt of all evl. --DK