Honored Contributor
Honored ContributorDave,
The host's board serial is just a part of the MAC address. When you plug-in your second board, you plug it into another PCIe slot, which makes default MAC address different. When you expand it to more boards, the serial of the motherboard will be different. Of course, motherboard manufacturers may not provide a unique serial address. There are also CPU serial numbers, etc. It is just one of the way to make the default MAC address more or less unique. If it so happens that it is not unique, then you can easily change it with ethtool/ifconfig. That can be persisted in a simple configuration file or be a part of the networking script that sets up the interface. If I were to hard-code and not allow the MAC address to be changed, then I'd of course get concerned. Otherwise, I don't see using a mixture of DMI serials, PCIe bus/slot identification etc. a worse solution than accessing on-board flash memory. In fact, I think it is a lot better.
