MAC Addresses

Certified Software Corporation tried to offer small blocks of MAC addresses for use on prototype and low quantity hardware where the expense of buying a "Organizationally Unique Identifier" is not warranted.

However, this was blocked by IEEE, for the details see the exchange of letters

Please note that the most significant byte of an Ethernet MAC address has two special bits in it. The LSB bit is set to one to indicate that this is a group address instead of an individual address. The next bit is zero if this is an universally administrated address (OUI purchased from IEEE). If this bit is one then the entire 48 bit address is locally administrated and no OUI is used.

If your product will be hidden behind a router this might be a way to go. There is a possibility that there will be a conflict, but with 46 bits being unique, the chances are very low. According to Thomas A. Ufer's listing, this strategy has been used by a number of companies. Here is a excerpt from that list showing locally administered MAC addresses along with a few new entries :

020406 BBN (Bolt Beranek and Newman, Inc.) internal usage (not registered)
020701 MICOM/Interlan DEC (UNIBUS or QBUS), Apollo, Cisco
020701 Racal-Datacom
026060 3Com
026086 Satelcom MegaPac (UK)
02608C 3Com IBM PC; Imagen; Valid; Cisco; Macintosh
02CF1F CMC Masscomp; Silicon Graphics; Prime EXL
02E6D3 BTI (Bus-Tech, Inc.) IBM Mainframes
2E2E2E LAA (Locally Administered Address) for Meditech Systems
2E4500-2E45FF OS-9 Lance driver
AA0000 DEC obsolete
AA0001 DEC obsolete
AA0002 DEC obsolete
AA0003 DEC Global physical address for some DEC machines
AA0004 DEC Local logical address for systems running DECNET
DEE900 Certified Software Corporation
F23F00-F23FFF Quanterra, Inc. (LS 32 bits from Dallas Serial Number Chip)

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