Hello all, after changing the hard drive on my laptop and reinstalling Debian testing, multicast is no longer working.
I'm quite sure this is a software issue, because it worked with the previous installation, it works from the windows partition on the same drive, and it works if the laptop is started from a Debian live. The broken system can definitely send multicast packages (they can be received on other machines), but it cannot receive any (tcpdump sees the outgoing packets, but do not see the incoming), not even the ones generated on the same system. Testing with a similar (both on hardware and software installed): $ iperf -s -u -B 224.0.55.55 -i 1 # on both laptops (`ip maddr` shows that the multicast group was properly joined) $ sudo tcpdump -s 5001 host 224.0.55.55 # on both laptops And running on the broken laptop $ iperf -c 224.0.55.55 -u -T 32 -t 3 -i 1 I can see on both tcpdump the packets, but only the iperf on the working laptop receives them. Running the same command on the working laptop, on the broken laptop neither tcpdump nor iperf receives anything. Some information: * The network is configured using networkmanager, and I tried this on different networks with the same results * I did not add or change any iptables rule * I did not add or change any route * I did not change (voluntarily at least) any related configuration * Multicast is enabled in the kernel * MULTICAST is enabled on the network interfaces * There are no special rules or registration on the router * `sudo sysctl -a | grep \\.rp_filter` reports all 0 * I compared one by one all the files in the /etc folder with the one from the previous installation, and with the ones of the other laptop), and I didn't find any relevant difference. * I compared line by line the output of `sudo sysctl -a` on the 2 systems, and I didn't find any relevant difference I tried anything that came in to my mind and any suggestion that I found on internet, but I did not find a solution. Now I run out of ideas... Can anyone help me solving this issue? Cheers, Daniele
