I have a NAS (Thecus N2100, IOP32x based) connected to my network using the
r8169 driver. When I start avahi-daemon on the NAS, the rest of the network
sees the multicast zeroconf announce packets being sent. If I wait five minutes
for the caches to expire in the clients and then ask another machine to resolve
the names the NAS is announcing, the lookups fail. The same happens with UPnP,
which also uses multicast UDP packets to work. My conclusion is that multicast
packets being received by r8169 are not being correctly handled.
I've also tried enabling ALLMULTI and PROMISC, which had no effect.