Two identical MBs' w/ the same MAC addresses

[videobruce]

I have two Foxconn N570SM2AA MB's;
http://www.foxconnchannel.com/en-us/product/Motherboards/detail_spec.aspx?ID=en-gb0000205

They have two built in ethernet controllers. Controller One on each board has the SAME identical MAC address as does Controller Two on each board. I was under the understanding that every ethernet device had a different address even the same model.

I was having a problem with these two PCs' talking to one another. My third box is a Laptop and there was no issue here. All are using XP Pro through a Westell VersaLink 327W DSL modem/router. It was also causing issues with the router as both boxes had the same MAC address.

Input??

[Sephis]

You could use macshift to change the mac address of one of the machines. I use it all the time. It can be found here (http://devices.natetrue.com/macshift/).

[FireMogle]

Some drivers allow you to change it in windows as well, look under advanced properties of the card for physical address.

[Adragontattoo]

Uninstall one NIC and reinstall it, it may pick up a different MAC address.

[CGR]

I would call Foxxconn and make them aware of the issue. Its possible if you have two boards with the same mac address then others they made could have that problem too.

While you are on the phone start an RMA for one of the boards.

[AlabamaCajun]

Could MAC address also be causing me to loose network connect? I moved a harddrive with Server 2003 to a different box and installed a new drice and XP on in the original box. Both boxen are on all the time but the XP box keeps loosing connectivity. It says it's connected but can't surf or share. The server box is not having a problem.

edit: Shutdown ZoneAlarm and Viola it started working. Something got set wrong somewhere.

[Adragontattoo]

yes.

[gangaskan]

I would call Foxxconn and make them aware of the issue. Its possible if you have two boards with the same mac address then others they made could have that problem too.

While you are on the phone start an RMA for one of the boards.


getting 2 nics with the same mac is a rare find lol, i'm sure some are being re used, but getting identical's are a rare find atleast in my experience. let alone on the same type of board

[VinnyTAMU]

getting 2 nics with the same mac is a rare find lol, i'm sure some are being re used, but getting identical's are a rare find atleast in my experience. let alone on the same type of board


Well finding the same MAC on an identical board is probably the best chance of finding identical MAC's. However I have heard of finding identical MAC's before, but at this point in the life of the MAC address I fail to see how this is happening. By my calculations there are 281,474,976,710,656 MAC addresses available. Also each manufacturer should have 16,777,216 MAC addresses available to them.

[gangaskan]

Well finding the same MAC on an identicle board is probably the best chance of finding identicle MAC's. However I have heard of finding identicle MAC's before, but at this point in the life of the MAC address I fail to see how this is happening. By my calculations there are 281,474,976,710,656 MAC adresses available. Also each manufacturer should have 16,777,216 MAC addresses available to them.


that is true, being the same manufacturer leads to more "error" or re usage of mac addresses?

[videobruce]

Uninstall one NIC and reinstall it, it may pick up a different MAC address.Isn't the address 'burned' (for lack of a better term) into the chip/card/device??

The temporary solution is to use the 2nd adapter on the 2nd MB w/ the different address.
The manufacture suppects a corrupted bios and suggested re-flashing both MBs', but directly in DOS, not through Windows which I did the first time using their "LiveUpdate". Anyway, how could the addresses from one MB transfer to another? The only common link is the router.
There are stickers on the MB w/ each address, but not in hexdecimal and all four addresses are different.

[gangaskan]

Isn't the address 'burned' (for lack of a better term) into the chip/card/device??

The temporary solution is to use the 2nd adapter on the 2nd MB w/ the different address.
The manufacture suppects a corrupted bios and suggested re-flashing both MBs', but directly in DOS, not through Windows which I did the first time using their "LiveUpdate". Anyway, how could the addresses from one MB transfer to another? The only common link is the router.
There are stickers on the MB w/ each address, but not in hexdecimal and all four addresses are different.


does it say MAC: 00-0e-03-05- etc ? in that fassion? the sticker should resemble some form of hex either it be bunched together or seperated by a . or a - and in some cases a space between the hex numbers :)

you could try a DOS flash, in some cases it might fix it, but if the bios was corrupt in any fashion, wouldn't the board not make POST?

[Stratus_ss]

Isn't the address 'burned' (for lack of a better term) into the chip/card/device??

in a basic sense yes.
All the mac addresses come stamped on the card from the manufacturer which identifies the card to the other devices on the network. Each manufacturer has its own specific section of the mac address which identifies them as the maker, which is why it is increasingly rare for the same mac address to be found and virtually impossible for it to be found outside of the same manufacturer

[gangaskan]

i think thats actually the term they refer to for saying embedded, flashed, or whatever you wanna call it.


each nic should have some form of flash ROM (EEPROM?) they use to burn the address into the card

[coin]

the first half of a MAC address identifies the manufacturer, massively reducing the range available. A small manufacturer will easily have enough addresses but the larger manufacturers will run into problems. Just thing how mnay things have network adapters stuffed in to them now.
Now that you can alter the MAC on most modern adapters manufacturers may be using the same MAC on each batch of boards (assuming each batch isn't too large!) or maybe using a round robin list of MACs for each board type. The only people likely to be buying several boards from the same manufactirer for use on the same network are companies and they are far more likely to be buying prebuilt (Dell, HP, IBM....)
It is still something of a long shot though to have managed to get two boards with identical NICS.