[U-Boot] Fw: u-boot soft and hard ethernet addresses

[Duncan Hare]

Dear Duncan,

In message <1814106598.1047276.1510787951141 at mail.yahoo.com> you wrote:
>
> Many board manufacturers "assign" this unique MAC address by printing it on a 
> sticker and sticking that on the board somewhere. It's pretty darn hard to 
> read a printed sticker in software, so we have to revert to solutions that 
> actually work.

Such solutions usually include a barcode reader attached to some PC
which is used when you commission the board.  And yes, in this case
it is mandatory that the MAC address(es) stored in the environment
(which gets initialized as part of the aforementioned commissioning
procedure) takes precedence over any MAC address(es) that might be
stored somewhere in the hardware.

> In the "clever things" department, protocols like IPv6 merrily broadcast your 
> MAC address across gateways on the big bad internet, so if you value your 
> privacy, you'll appreciate the possibility to change your MAC address at will.

Right, this is another of a list of reasons why changing the MAC
address makes a lot of sense.

Best regards,

Wolfgang Denk

-- 

Wolfgang
I agree. Some Ethernet adapters/chip/cell libraries have burnt in Ethernet addresses.
Some do not.
I'm not saying anything is good or bad, I am,  stating , if one wants to use the burnt in address, 
if it exists, there is a mechanism in U-Boot to do so.

I carefully did not state an opinion. Having a soft coded mac address makes replication of software 
on units complex. Having a burnt in hardware address makes software replication simple, but addscomplexity to hardware manufacturing.

Having stated that, there has to be a unique address for the device somewhere, either in the 
hardware or software. If in hardware the manufacturer provides the address, If in u-boot the 
unique address has to be managed by the customer, and passed to the OS launched by u-boot.

IP is the second network architecture which I've used on which expanded its address space,  the first wasIBM's SNA. The expansion in both architectures was curtailed, or delayed, by having gateways, in IP's case NAT gateways, 
in IBM's SNA it was SNI - SNA Network Interconnect.

Because of the extensive use of gateways, the risk of a device's mac address being braodcast to, is hopefully,limited by the gateway. If it is not then one need to buy a better gateway which protect one's privacy.

Regards
 Duncan Hare

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