I use Squeezeplug/Max2Play on a Raspberry Pi as a mobile music playing device. So usually WiFi is used. Sometimes the WiFi signal is too weak so that I use a network cable.
But every time I plug a network cable in the Linux distribution behaves weird. The Player name/machine name seems to get announced on both network interfaces and it seems that the default route is not properly set. As a result my Laptop Firewall gives me a message that an „ARP cache poisoning attempt“ has been blocked. And the Raspberry is not responding properly to network requestst anymore (from iPhone, iPad, Laptop, …).
When I remove the WiFi USB stick and make use of the network cable only the player works fine.
I did not see this behaviour on ny other linux machine before. Using WiFi and network cable never was a propblem.