ethtool get permanent MAC address returns all 0's

Question

I need to read permanent (burned-in) MAC address of network adapter. Since MAC address can be easily spoofed, I need to read the real one which is written on EEPROM. I need to do it using C++ on Linux.

I tried using ethtool which is quite good and works fine. However on some systems it does not work as intented.

ethtool -P eth0

returns this:

Permanent address: 00:00:00:00:00:00

and

ethtool -e eth0

returns this:

Cannot get EEPROM data: Operation not supported

---

Network Adapter has following info:

• driver: ucc_geth
• version: 1.1
• firmware-version: N/A
• bus-info: QUICC ENGINE

Linux kernel version is: 2.6.32.13

Question is: Can i fix this issue with any update(driver, kernel etc)?

Additionally, I make the same ethtool calls with ioctl function in C++. Is there any way to fix this inside the code? Or is there any other way to get the permanent MAC address from EEPROM?

Answer 1

If you haven't find the answer yet, you might want to check this out.

https://serverfault.com/questions/316976/can-i-get-the-original-mac-address-after-it-has-been-changed

Answer 2

Take a look at a couple of things.

1. Look at packets on the wire (using a sniffer) emanating from this NIC and see the MAC address being used.
2. Look at the output of "ifconfig -a eth0". If the MAC address is the same as on the wire, then you can get that MAC address using the mechanism that ifconfig uses.