Ethernet Shield Problem

Hi! I have got an Arduino Ethernet Shield (PoE). The problem is that i can't turn on it only with an ethernet cable. Why? However if i connect it to Arduino Uno it does turn on but if i connect that to PC with a ethernet cable, it doesn't connect to the web! Is it defective?

Salve! Possiedo un Arduino Ethernet Shield (PoE) Il problema è che se la collego con il cavo ethernet non si accende! Perchè? Comunque se la connetto ad arduino uno si accende ma se la collego al pc non si connette a internet! E' difettosa?

Do you have a PoE injector or similarly capable switch on the other end of the Ethernet cable? Standard switches or PCs don't provide PoE.

No but it isn't a big problem. The question is why it doesn't connect to the web?

No but it isn't a big problem.

I think that having no power is a big problem for an Arduino.

The question is why it doesn't connect to the web?

You didn't tell us anything about your setup, how do you expect us to determine what might have gone wrong on your side? I'd guess it's either because your Arduino doesn't have power (see above) or it's a network problem but you didn't tell us how your network looks like nor did you post your sketch.