@(#)Using the on-board MAC address 14 AUG 2000 Rob Thomas robt@cymru.com
Using the on-board MAC address instead of the system-wide MAC address

By default, a Sun box will utilize the MAC address contained within the
boot PROM for all Ethernet interfaces.  While this is suitable for hosts
with a single NIC, or hosts with more than a single NIC each in a dis-
tinct hub or switch, this can cause great woe to an entirely switched
network.  To configure the Sun host so that it will utilize the MAC
addresses on the NIC cards, we must make a change to the EEPROM settings.

This is done with the eeprom(1M) command.  To check the value, first
query the value of local-mac-address? in this manner:

host# eeprom local-mac-address?
local-mac-address?=false

A-ha!  This host is using the PROM MAC address, thus each NIC has the
same MAC address.  To change this, we must set the value to true in this
manner:

host# eeprom local-mac-address?=true

Then check it to be sure:

host# eeprom local-mac-address?
local-mac-address?=true

That's it!  Reboot and the host will come up with distinct MAC addresses
for each NIC.  Caveat:  Some network drivers do not have a unique MAC
address, and will continue to use the MAC address in the PROM.

If you are forced to make this change at the ok> prompt, it is done
thusly:

ok> setenv local-mac-address? true

Rob Thomas, robt@cymru.com
http://www.enteract.com/~robt