Valid usecase:
Long ago Nokia made firewalls, their CheckPoint IP-220 was a nice short 1U box, before the existence of Mini-ITX.
Their own OS "IPSO SB" was originally derived by Ipsilon Networks from FreeBSD 2.1-STABLE and cross-compiled on FreeBSD 2.2.6-RELEASE and 3.5-RELEASE platforms. I think with additional Java (Solaris alike) console-interface modules, just like on JunOS of Jupiter.
Anyway, I installed FreeBSD on it, an early version 5 or late version 4.
As it didn't have VGA, I would do a generic install in one server, and swop the disk to the Nokia.
However, it's BIOS strictly demanded a specific MAC, otherwise the triple ethernet interface wouldn't communicate at all.
So, when set to the original MAC's, it then would came up fine
(and no: 100% certain that was not DHCP lease related).
Today I revisited this old tread. Busy on a project with a lot of tiny devices. Identical hardware, different tasks. Controllers with each it's own software.
To keep network administration tight and addressing fixed and to spare me a lot of mutations during development I give each device a cloned MAC.
Reading above problem with receiving a lease and then modify, I was about to try above suggested twoliner, but in the opposite order:
ifconfig_re0="ether 00:C0:4C:00:37:FB up"
ipv4_addrs_re0="DHCP"
But even before I was able to try the above truly connected in the network, simply a
ifconfig_re0="DHCP ether 00:C0:4C:00:37:FB"
did already the job, without problem.
link, lladdr and ether have the same meaning for /sbin/ifconfig.
While being aware you wrote this 10+ year ago...
When using 'link cu:st
m' (in ifconfig lines in rc.conf) then I do see 'ether cu:st
m' AND 'hwaddr or:ig:in:al'
When using ether then I don't spot this 'hwaddr' being mentioned anymore.