mac adress ethernet shield

i have a ethernet shield with a sticker on it. is this the mac address? And how i have to use it in the code because I always find this type of mac address { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }

do i have to adapt the code on the sticker in a certain way ??

That is your mac address.

mac[] = { 0x90, 0xA2,0xDA,0x00,0x99,0x56 };

Is the mac address hard coded or can it be changed in ethernet code such that multiple ethernet shields on a lan can have different mac addresses?

The mac address on the bottom is not hard coded into the device as far as I can tell. You can change it to anything you want, but if you get multiple cards, you must have different mac addresses on each, or there will be real problems on your localnet. Using this mac address would prevent that. I can change the mac addresses on the interfaces on my routers. It is not unusual to have that function on commercial equipment.

Thanks!! Topic can be closed.