repeated mac address

Hi:

I bough a bunch of Intel 10/100 pro from ebay and many of them have the smae mac addresses such as "00:a4:c0:91:d2:9c" or "00:b4:c0:91:d2:9c" under freebsd 5.x.

how could that happen? have someone done something on those mac addresses?
10 answers Last reply
More about repeated address
  1. It may be resetting them to known-to-work-with-freebsd mac addresses. Try w/ a different operating system - they'll probably be different.

    They permanently are different, but the OS or software can modify them in the software.
  2. Quote:
    It may be resetting them to known-to-work-with-freebsd mac addresses. Try w/ a different operating system - they'll probably be different.

    They permanently are different, but the OS or software can modify them in the software.


    jus tried them under xp, none of them are working. they all have the same address "00:a4:c0:91:d2:9c" or "00:b4:c0:91:d2:9c"
  3. How are you getting the MAC addresses of the cards?
    In windows, you can do a ipconfig /all from a command prompt.

    They should not be different unless some software is changing it.

    I can't even find out the manufacturer of "00:b4:c0" or "00:a4:c0" on the IEEE page.

    Was this a really shady deal on ebay??? :P
  4. Quote:
    How are you getting the MAC addresses of the cards?
    In windows, you can do a ipconfig /all from a command prompt.

    They should not be different unless some software is changing it.

    I can't even find out the manufacturer of "00:b4:c0" or "00:a4:c0" on the IEEE page.

    Was this a really shady deal on ebay??? :P


    yes, i think i was screwed by the deal:

    fxp0: warning: unsupported PHY, type = 0, addr = 0

    oh well
  5. Also, from intel... might be able to help you determine what the MAC should be..

    "What do the numbers and letters on the bar code label on Intel adapters mean?
    There are various numbers and letters printed on the bar code on Intel adapters. Depending on the model and age, these numbers can appear in different locations. Here is a general guide to the markings.

    * 6 digits - 3 digits (e.g. 761767-003) - This is the adapter printed board assembly number. The first six digits (which may include letters) are the number we use to absolutely identify the product. The 3 digits following represent minor revisions that have no effect on functionality and can be ignored.

    * 12 characters (e.g. 0007E90018EA) - This is the MAC address, also known as the Ethernet ID. This address is stored on the card. Every network adapter built has a unique MAC address. This number uniquely identifies the adapter on the network.

    * 5 digits (e.g. 36013) - This number is a manufacturing code used by Intel for internal tracking purposes.

    Note: There are other 6 digit - 3 digit numbers on the adapters at various locations, such as the number on the metal bracket and the MP and PB numbers silk-screened onto the board. These represent individual component part numbers and should be ignored when identifying the adapter. "

    http://www.intel.com/support/network/adapter/pro100/sb/cs-008491.htm
  6. Quote:
    You might want to read this...
    http://64.62.136.189/freebsd-hackers@freebsd.org/msg17322.html

    Go google! :D


    Thanks. But I hardly see it ould OS related issue. It happens with XP too. plus, the same 82559 chip cards, 10 out of 20 are good.

    the issue is whether we can restore the mac addresses that were printed on the cards (the bar code numbers).
  7. Quote:
    You might want to read this...
    http://64.62.136.189/freebsd-hackers@freebsd.org/msg17322.html

    Go google! :D


    Thanks. But I hardly see it ould OS related issue. It happens with XP too. plus, the same 82559 chip cards, 10 out of 20 are good.

    the issue is whether we can restore the mac addresses that were printed on the cards (the bar code numbers).

    I have seen some reference on the internet to cards that were illegal copies using repeat MAC addresses. I can't remember where though.
  8. I'm not sure if you can reset the mac addresses. They're using an eeprom, so its possible, but i doubt its allowed. You might want to try contacting Intel and see if they tell you anything.

    MAC's are supposed to be unique. On the other hand, you have the printed MAC addresses on the NIC. But if they're illegal cards, then you might be out of luck... :?
  9. First off *BSD is great, I love all Unix OSes but especially the open source ones :D


    You can change the MAC address during boot in most OSes including Linux and BSD :D

    http://en.wikipedia.org/wiki/MAC_address

    Changing the MAC address permanently can be trickier but can be done see here:

    http://en.wikipedia.org/wiki/MAC_address#Change_The_MAC_Address_Permanently


    By the way you can use ethernet cards with the same MAC but they can't be on the same ethernet LAN.
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