How do I over-ride eth-adapter's physical 48-bit MAC address?

[David Cook]

In Win-XP, there must be a way to coerce an ethernet-adapter to
NOT use the phyical MAC address built into the card, but instead
use some other (software) MAC address value.

But, I can't find anywhere to set/configure a NEW value. How/where
do I do this? (Is there an official UI or do I need to hack the registry?)

TIA...

Dave

 

[Gary Davis]

The physical MAC address is burned into a ROM on the NIC card and is a
unique number.
Why are you trying to change it?

 

[David Cook]

Why do you need to know WHY?

I asked HOW.

(It's done routinely, so I know it's possible.)

For example, on Linux, look at their 'ifconfig' cmd, where
they show you the syntax for how to override
the burned-in value and use some other value on a Linux system.

Either you know how to on Win-XP or you don't. If you don't,
keep quiet and let someone who DOES know how answer this.

(Sorry I'm not trying to be rude. I'm just after the facts. It can be
done or it can't. If it can, how.)

 

[Gary Davis]

Getting a little hostel maybe you should switch to decaf.

Go to your network settings and in the configuration of your NIC card under
advanced there may be a setting for "Network Address". My 3Com has this I'm
not sure what type of NIC you run.

I asked why you wanted to change the MAC address because it has to do with
IP routing and the only reason I can think of for changing this address was
to hijack someone's connection.

 

[David Cook]

In answer to concerns about WHY one might want to know how
to do this, look at the website:
http://www.klcconsulting.net/smac/
So, obviously a LOT of people have various reasons why they want
to do this. Enough people that the folks at this website provide
their own software-solution to this issue.

I'm just trying to understand whether needing a PROGRAM to do this
is really necessary. Is it?

(If so, then why does Win-XP not provide at least a registry-approach to
solving this issue? Linux allows it trivially on the cmd line. Yet, for
some
unknown reason, it is a big dark mystery for Win-XP to do this?)

TIA...hope this helps explain 'why'...

Dave

 

[Bruce Chambers]

Greetings --

This would be a feature of the NIC's drivers and configuration
utility, if the NIC has been designed with the capability of altering
its MAC. There's no way, using WinXP's native tools, to do this.

Bruce Chambers

--
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having both at once. -- RAH

 

[Sarge]

In answer to concerns about WHY one might want to know how
to do this, look at the website:
http://www.klcconsulting.net/smac/
So, obviously a LOT of people have various reasons why they want
to do this. Enough people that the folks at this website provide
their own software-solution to this issue.

I'm just trying to understand whether needing a PROGRAM to do this
is really necessary. Is it?

Apparently not. Your question is answered in a link from the very page you
reference:

"MAC Address Spoofing for Windows 2000, XP and 2003 Servers":

http://www.klcconsulting.net/Change_MAC_w2k.htm

 

[Gary Tait]

The physical MAC address is burned into a ROM on the NIC card and is a
unique number.
Why are you trying to change it?

More recent cards have in on an EEPROM, which you can re-program, if
you can find the app to do it (I am lucky, the manufacturer of the
chip on my NIC has an downloadable app to adjust most card parameters,
including the MAC).

One may want to change it to trick WPA (which counts 3 votes in the
WPA scheme)

 

[Alex Nichol]

This would be a feature of the NIC's drivers and configuration
utility, if the NIC has been designed with the capability of altering
its MAC. There's no way, using WinXP's native tools, to do this.

Add:
Also be aware that the MAC address carries treble weight in assessing if
the hardware is unchanged for purposes of Windows Product Activation.
Changing it could be the last straw

 

[Daniel L. Belton]

In Win-XP, there must be a way to coerce an ethernet-adapter to
NOT use the phyical MAC address built into the card, but instead
use some other (software) MAC address value.

But, I can't find anywhere to set/configure a NEW value. How/where
do I do this? (Is there an official UI or do I need to hack the registry?)

TIA...

Dave

Nope... The MAC address is tied to the hardware and can't be changed.

There are some routers that will use a the MAC address from the NIC
instead of the one from the router to be used for authentication
purposes. Linksys routers do this, and I am sure there are plenty of
others.

 

[Daniel L. Belton]

The physical MAC address is burned into a ROM on the NIC card and is a
unique number.
Why are you trying to change it?

My guess would be that he's trying to spoof someone else's MAC address
for authentication purposes. Some ISP's use it instead of sign on
information.

 

[David Cook]

There are many legitimate reasons (not break-in related) for wanting
the MAC-address in outgoing packets to be something other than
the value burned into a particular adapter's hardware.

One example is that 'DECNet' (a network protocol from Digital Equip Corp)
software made use of this feature of putting its own constant value
(AA-00-04-00-??-??) [I now forget the last 2 byte-values]. And other
well-known client/server protocols do something similar, so that multi-homed
(using multiple-adapters yet wanting the outgoing traffic to appear
identical)
things will work correctly. This is just some of the reasons why Linux/Unix
systems make it easy to override the builtin value.

Yes, I am aware that Win-XP might be using a MAC-address as part of
some algorithm to uniquely identify a machine. However please note
that Microsoft's decision to do that should IN NO WAY interfere with
it's customers ability to independently override the value in the use of
ethernet adapters. So that issue is orthogonal to this discussion.

So, the question still stands: Is there or is there not some way to
configure
such a change of MAC address on Win-XP (without resorting to third-party
software)
to address these legitimate reasons for wanting to over-ride the physical
MAC address?

From everyone's silence so far, one can only conclude that either the answer
is NO, or else everyone is too afraid or whatever to explain how (best) to
do it? Can't someone who speaks somewhat 'officially' for Microsoft
please answer this HOWTO question with a statement of fact on
how it can be accomplished or else say that Microsoft no longer officially
supports the legitimate reasons for doing this?

(God, has Sept 11th put everybody into 'cover your ass' or 'he must be
some sort of terrorist' mentalities?)

 

[Daniel L. Belton]

There are many legitimate reasons (not break-in related) for wanting
the MAC-address in outgoing packets to be something other than
the value burned into a particular adapter's hardware.

One example is that 'DECNet' (a network protocol from Digital Equip Corp)
software made use of this feature of putting its own constant value
(AA-00-04-00-??-??) [I now forget the last 2 byte-values]. And other
well-known client/server protocols do something similar, so that multi-homed
(using multiple-adapters yet wanting the outgoing traffic to appear
identical)
things will work correctly. This is just some of the reasons why Linux/Unix
systems make it easy to override the builtin value.

Yes, I am aware that Win-XP might be using a MAC-address as part of
some algorithm to uniquely identify a machine. However please note
that Microsoft's decision to do that should IN NO WAY interfere with
it's customers ability to independently override the value in the use of
ethernet adapters. So that issue is orthogonal to this discussion.

So, the question still stands: Is there or is there not some way to
configure
such a change of MAC address on Win-XP (without resorting to third-party
software)
to address these legitimate reasons for wanting to over-ride the physical
MAC address?

From everyone's silence so far, one can only conclude that either the answer
is NO, or else everyone is too afraid or whatever to explain how (best) to
do it? Can't someone who speaks somewhat 'officially' for Microsoft
please answer this HOWTO question with a statement of fact on
how it can be accomplished or else say that Microsoft no longer officially
supports the legitimate reasons for doing this?

(God, has Sept 11th put everybody into 'cover your ass' or 'he must be
some sort of terrorist' mentalities?)

Actually... It wasn't Microsoft's decision to tie the MAC address to
the hardware.

The first part of the MAC address is used to identify the hardware
manufacturer. Each manufacturer has a unique identifier. Microsoft had
nothing to do with this decision.

To me, if a network protocol is tied to a particular manufacturer of a
network card, then there is a good reason for it, and you could be
asking for lots of problems if you try to use a different card. It
might not support the protocol properly, and you could get all kinds of
errors.

But to answer your original question...

No, there is not a way to change the MAC address without third party
software... WinXP doesn't have that functionality in it.