Changing MAC address from LAN port

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MallAudio

95 posts

Master Geek

#23588 3-Jul-2008 15:55

Any ideas on how to manually change MAC address on LAN port without buying software??

PenultimateHop

637 posts

Ultimate Geek

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#142590 3-Jul-2008 16:05

What NIC? What OS?

Most NICs support software MAC changes (bear in mind the burned in address in the PHY won't actually change, but the NIC will use the new software-supplied MAC).

In Windows, you can generally do this through Control Panel -> Networking -> LAN -> Configure -> Advanced -> and look for "Locally Administered Address" or "Hardware address", but it could have other parameters depending on the NIC/driver type.

Under Unix-type machines, ifconfig <dev> hw <new mac> should work; or you can use ethtool.

Why do you want to do this?

MallAudio

95 posts

Master Geek

#142608 3-Jul-2008 16:33

we have cloned machines which we run on a VPN network and using GHOST to clone, it copies all hardware MAC #'s, so having compatability issues when clients are all loggin on using same LAN MAC addresses... when one logs on the other gets booted...

Running XP SP2

tonyhughes

Hawkes Bay
8476 posts

Uber Geek

Retired Mod

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Lifetime subscriber

#142617 3-Jul-2008 16:48

Havent thought this right through sorry, as I don't usually have issues with MAC addresses, but..... what about uninstalling/reinstalling the NIC on each client?

MallAudio

95 posts

Master Geek

#142629 3-Jul-2008 17:09

have tried but to no avail... although... i must add... have been playing around with settings etc on a new box that we are only trialling (ASUS PX-20) which doesnt have a default network adapter since i cloned over the top with uncompatable drivers etc... they are running thin client versions of windows on site PC's so don't have the option of changing settings manually through hardware managment...

PenultimateHop

637 posts

Ultimate Geek

Trusted

#142649 3-Jul-2008 18:03

Windows should always use the HW address of the NIC in the machine by default - you have to go out of your way to tell it NOT to use the BIA. I don't think that it's likely to inherit it via Ghost, but I could be wrong as I don't know a lot about Windows or Ghost.

What do you mean by "VPN network [...] one logs on and the other gets booted"? MAC addresses are only relevant to the local L2 segment, generally not to VPNs.

MallAudio

95 posts

Master Geek

#142814 4-Jul-2008 08:07

GHOST does an exact replica of the PC you source from- entire registry and all... not like IMAGE-X which only copies everything under the HAL... When i do my ipconfig on my server the sites that are dropping away and popping up (rotating) are not working because the Network cards say they are the same thing, but with 2 IP address coming from it... The VPN program we use is very basic and doesnt seem to like the fact that the MAC addresses are the same... Beats me!! its all good though... am just going to use SMAC and re-config them all manually...

MallAudio

95 posts

Master Geek

#142817 4-Jul-2008 08:10

It could have only been one of a few things anyway... IP address... Computer name (or another computer name on client network clashing with ours) or something to do with the HAL... in this case the only common factor between the PC's that is being seen by my server is the MAC address on the network card...

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PenultimateHop

637 posts

Ultimate Geek

Trusted

#143086 4-Jul-2008 21:25

Well, I guess you've found your solution. I am still curious about the problem though:

1) I'm not a Windows or Ghost expert, but it seems odd to me that the MAC would be persistent in Windows. Surely it is dependent on when the machine boots? All our corporate PCs are built from a single build image, and we don't have duplicate MACs (NB: I don't work for IT, so I'm not sure how the image process works).

It just seems *odd* that the MAC would be stored anywhere in Windows if you hadn't specifically configured it.

What does an "ipconfig /all" show under "Physical Address" for the Ethernet card, on two separate PCs?

2) You state your VPN server sees their MAC address. If they're connecting over a VPN, then I'm not sure how you would see the MAC, except perhaps for PPPoE. Any MAC related issues would be on seen on the local LAN the machines are physically connected to; not via a VPN.

Simonm

181 posts

Master Geek

#145074 8-Jul-2008 21:59

Are you using SYSPREP at all in your ghosting process?