I got an Ethernet shield via amz ( http://amzn.com/B00GIDHZHE ) a year ago and just getting around to trying it out. Using the simple WebServer example. I've tried Ethernet.begin(mac, ip); with and without the ip parameter to use DHCP. On my router I am not seeing the arduino on the list of connected devices but router does show that the port is sending data/packets and receiving a very small amount of data/packets when I have the arduino connected.
This ethernet shield does not have a MAC sticker on the bottom so I have left the default value in the code.
Any tips on how to debug this problem and verify the ethernet shield is ok?