[avahi] avahi-daemon stops working after undetermined period of time

[Kristian Domke]

OK, answering myself.

I found the problem, at least in my system. Obviously there is  
something wrong with some network cards and multicast in Ubuntu / Linux.

I read about it in the german Ubuntu Wiki: http://wiki.ubuntuusers.de/Avahi#Avahi-im-Netzwerk

The solution is a simple

sudo ifconfig eth0 allmulti

To make it restart save add the following in the file /etc/network/ 
interfaces in the section for the relevant NIC (take care of  
indentation):
post-up infconfig eth0 allmulti

Hope that helps

Kristian