The VideoLAN Forums

I have a really strange problem with my PC and I don't even know how to explain it.
I run an instance of VLC which broadcasts the data of a video file on a multicast address and then I run a different instance on the same PC for receiving and displaying the video.
This worked fine and without any problems when I was working on Windows XP Home Edition SP2. Last week I have bought and installed Windows XP Professional Edition SP2 OEM and when I tried to do the same the receiver did not accept anything.
After numerous of tries and experiments I accidentally found out that when I use a Packet Sniffer Application the time I transmit the video everything works fine again. but only when the Packet sniffer (Ethereal) is active and sniffing packets.
This happens with everything I try --> VLC, JMF, two manually created java classes (sending and receiving)

Does anyone has a hint about what is going wrong?

My PC :
HP nx9420
Windows XP Professional SP2
Kaspersky Internet Security 7
Windows Defender

Anything else you need please let me know

Thanks

It could be that your client under the "new" OS doesn't respond to IGMP queries like it should, that's what I have with my new Dell Latitude D-420 laptops. The D-820's with comparable OS configuration work fine.
As I didn't found anything on the Dell website about it, and I read more posts with people having this kind of trouble, I guess going through the Microsoft knowledge base might be a good idea.

Teta

Yes but how do you explain when I sniff the packets with Ethereal Packet Sniffer everything works just fine? The sniffer just collects information about every packet sent from my interface card.