MAC address change question


I recently travelled to Seattle for a meeting and decided to play with
changing my MAC address and seeing how that would affect my network
access.

My configuration:

HP Pavilion zd8000 laptop
Mandriva 2006 Linux

Now, if I change my MAC address, either directly using ifconfig or with
macchanger, everything *seems* to work right locally on the machine,
but none of the DHCP servers I've played with will give me an ip address.
This was true for the wireless server at my hotel room, and for the Cingular
service here at SeaTac (where I'm waiting for a plane).

This is true even if I put the change early in the boot up sequence.

If I change my MAC address back to the "real" hardware address, Cingular
will give me an ip address no questions asked.


So for example, if I:

<boot up with network down>

% /etc/init.d/network start
% ifup wlan0 (I don't have my wireless come
up automatically)

I get an ip address from the dhcp server
just fine.

Then:

% /etc/init.d/network stop
% macchanger -e -a wlan0
% /etc/init.d/network start
% ifup wlan0

I get a time out and no dhcp response,
even though ifconfig wlan0 gives the
new mac number as the HWaddress.

Then:

% /etc/init.d/network stop
% macchanger -m <original number>
% /etc/init.d/network start
% ifup wlan0

I get an address from the dhcp server!

Everything I know to check looks fine with
respect to the change in MAC address having
been done correctly.

I don't understand why this doesn't work.
Obviously I need to learn something. Any
pointers would be appreciated!

Thanks in advance,

billo
.

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