Replacement motherboard, renumbered NICs and dvd drives?

NoOp glgxg at
Mon Feb 25 16:14:10 UTC 2008

On 02/25/2008 07:23 AM, Leo Cacciari wrote:
> Il giorno lun, 25/02/2008 alle 13.56 +0000, Adam Funk ha scritto:
>> The computer store has replaced my faulty motherboard twice recently,
>> and each time the number of the on-board LAN (the only ethernet device
>> present) has gone up (eth0 -> eth1, and now eth2).  Does anyone know
>> why, and is it possible to reset it?
> I belive this is due to the old NIC being included
> into /etc/udev/rules.d/70-persistent-net.rules. AFAIK, each time the
> system sees a NIC, it inserts a entry there, thus recording a 'static'
> name ethN for the card, thus allowing per-card configuration. I _think_
> you can safely remove the entries referring to the older cards and
> rename the one you have now (the last one) as eth0, but check the
> udev(7) man page to be sure.

Leo is right. I remember this one as I had the same problem awhile back.
Previously it was /etc/iftab in older releases:

You can safely edit and/or delete in

However, word of advise: be sure to do an 'sudo ifconfig -a' and print
out before modifying /etc/udev/rules.d/70-persistent-net.rules. Make
sure that you get the mac addresses correct & enter in alpha characters
in lower case... /etc/udev/rules.d/70-persistent-net.rules seems to have
problems with upper case:

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