Hi,

First of all please let me explain what is my requirement. Using single physical interface I want to create three 
network interfaces having different IP and MAC addresses.

For that I created three VLAN interfaces (vlan0, vlan1 and vlan2) on physical interface (en0) using ifconfig.

e.g.
ifconfig vlan0 create
ifconfig vlan0 vlan 2 vlanif en0

Now, I can assign different IP address for all three VLAN interface using ifconfig but MAC address of all these 
interfaces is same as its parent's(en0) MAC address .

To change MAC address I tried...
# ifconfig vlan0 down
# ifconfig vlan0 link new_mac_addr active 
# ifconfig vlan0 link old_mac_addr delete
...

This works for en0 but it did not work for vlan interfaces.

So please can anyone tell whether is it possible to change MAC address of VLAN interface? If yes please let me know how 
it can be done?

Thank you very much
Apurva