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Every time I start my network interface, I get a different MAC address! If I try to force the MAC address value using

ifconfig usb0 hw ether AA:BB:DD..:FF

it will be again different after issuing

ifconfig usb0 up

What make this MAC address change? How can I stop this to happen and stick to HW burned MAC address?

I am using a panda board (omap4/armv7) on a angtrom distribution. The inteface is a smsc95xx USB 2.0 Ethernet.

Thanks, Fabrice.

Fafaman
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2 Answers2

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There is an issue with the smsc95xx driver.

[PATCH] smsc95xx: generate random MAC address once, not every ifup

There is also something in the work to get a 'repeatable' MAC generation going, but it didn't get much uptake:

Beagleboard xM smsc95xx MAC address from die id

Edit just searching for smsc95xx mac address gives a ton of competing patches, with some more explanations (the smc hub+NIC frequently doesn't have an EEPROM, so also no MAC)

sehe
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  • Thanks! After reading the patch description I have an extra question: If I use the patch, I still get to have a random MAC addr each time I reboot, but my IT team configured their DHCP server to provide me with an IP based on a stable MAC address... It seams MAC addresses are set random in many systems now that does not fit with what I learned about them ...in the 90's... How do I get a fixed IP with a random MAC? – Fafaman Sep 28 '11 at 10:00
  • @Fafaman: If you follow the search link you'll find patches that allow setting a fixed MAC as part of the module parameters (and possibly on the fly?) - within the first few hits as well :). One patch even hardcodes a MAC address, if I saw correctly in the quick glances – sehe Sep 28 '11 at 10:37
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MAC addresses are typically coded in the chipset, but mutable.

It might be that your distro is randomising it for security reasons.

spraff
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