MAC address change on 21040 "Tulip" Ethernet Adapter does not work

[paul at vanmaaren.org]

Hello,

On a FreeBSD 4.9 machine I want to change the MAC address on a DecChip
21040 "Tulip" Ethernet Adapter. So I type the following:

# ifconfig de0 down
# ifconfig de0 link 00:00:00:12:34:56
# ifconfig de0
de0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
        ether 00:00:00:12:34:56
        media: Ethernet autoselect (10baseT/UTP)
        status: active
# dhclient de0

In another window:
# tcpdump -n -e -i de0
tcpdump: listening on de0
12:33:40.010093 8:0:2b:e6:d4:26 ff:ff:ff:ff:ff:ff 0800 342: 0.0.0.0.68 >
255.255.255.255.67:  xid:0x8a4f8e11 ether 0:0:0:12:34:56 [|bootp] [tos 0x10]
12:33:40.019187 0:10:60:e7:6a:39 0:0:0:12:34:56 0800 342: 172.16.0.1.67 >
172.16.0.33.68:  xid:0x8a4f8e11 Y:172.16.0.33 S:172.16.0.1 [|bootp] [tos 0x10]
12:33:40.105308 8:0:2b:e6:d4:26 ff:ff:ff:ff:ff:ff 0806 42: arp who-has
172.16.0.33 tell 172.16.0.33

>From the above is clear that the specified mac address is not used for
putting things on the wire. It is used inside the packet though. Is this a
known problem, and if so, can it be fixed?

--
Regards,

Paul