IGMP

I have one vista machine on a client's LAN with all other clients being XP.
(and some Linux) In a routine audit of network traffic I noticed this one
machine is singularly generating around 80% of all the traffic on the LAN,
and this traffic is unnecessary.

I have shut down just about everything inbound and outbound with advanced
firewall. (which is one nice feature, BTW!) The only think I have running,
according to the firewall, is IPv4 file and print sharing and DHCP.

But I still see IGMP multicast membership announcements, and further an
address starting off with 169.x.x.x. The multicast address used is
224.0.0.253. I have googled the ****ens out of this matter, and came up with
a slew of registry tweaks from "the cable guy."

I shut off teredo and all IPv6 via the registry. I searched the registry for
IGMP, "v3 membership report" and the above addresses, and found nothing
pertinent.

My question is what do I have to do to shut off this traffic? We have no use
for this traffic, and every reason to stop it.

BTW I also shut down EVERY service, one by one, and checked the traffic
after each. Not even shutting down Windows update stopped this multicast.

Any help greatly appreciated. So far so good with this Vista machine, except
it's a bit to chatty on the network.

cat