Is it possible to have two devices with the same MAC address?

Having two devices with the same MAC address on the same Local Area Network is bad because they will confuse switches, they will both attempt to respond to the same traffic - it's a mess, devoutly to be avoided. The very design of Ethernet (and thus 802.3 and 802.11) require unique MAC addresses on every LAN. read more

In order for a network device to be able to communicate, the MAC Address it is using must be unique. No other device on that local network subnet can use that MAC Address. If two devices have the same MAC Address (which occurs more often than network administrators would like), neither computer can communicate properly. read more

Every device on a network that is not passing through a proxy or translator must have a unique address. Otherwise, communications to of from those devices will become unpredictable. If two devices have the same address on the same LAN and detect each other, one will shut itself down. read more