Devices with MAC addresses that start with 00-00-81 were manufactured by Bay Networks

Device ManufacturerBay Networks
PO Box 58185
Santa Clara CA 95052-8185
Estimated Devices with 00-00-8116256250
Estimated Total Devices From Mfg48768750
Other MAC Addresses00-E0-7B, 00-00-A2
Address Examples