have a machine which had an onboard intel e100 which I switched off in the
bios. I put in a realtex gigabit card instead. That did not work well, so I
took it out and put in an intel gigabit card. Now, each time the ethernet
device went up by 1. Thus the internal was originally eth0. Then the
realtek was eth1, and the intel gigabit was eth2. But each time commented
out the appropriate line in /etc/modprobe.conf before booting up with the
new card, but the new card still had the higher number. Where in the world
is the system remembering that once upon a time there used to be a
different card which had eth1 or eth0? Why is the new card not numbered
eth0?

Thanks.

Bill Unruh <unruh@physics.ubc.ca> writes:

> have a machine which had an onboard intel e100 which I switched off in the
>bios. I put in a realtex gigabit card instead. That did not work well, so I
>took it out and put in an intel gigabit card. Now, each time the ethernet
>device went up by 1. Thus the internal was originally eth0. Then the
>realtek was eth1, and the intel gigabit was eth2. But each time commented
>out the appropriate line in /etc/modprobe.conf before booting up with the
>new card, but the new card still had the higher number. Where in the world
>is the system remembering that once upon a time there used to be a
>different card which had eth1 or eth0? Why is the new card not numbered
>eth0?

>Thanks.

As always you post on netnews and the answer comes back-- this time by
telepathy. I found the location where the numbering gets done --
/etc/udev/rules.d/62-create_persistent.rules

Lines like
SUBSYSTEM=="net", ACTION=="add", ENV{INTERFACE}!="*.*",
SYSFS{address}=="00:0a:cd:15:84:d0", NAME="eth1", ENV{MDV_CONFIGURED}="yes"

Ie udev changes the number of the ethernet devices according the mac
address of the card. This is useful I am sure in many cases, where y ou
want consistancy of naming if you have multiple cards, so the system does
not randomly assign a number. However in my case it was a pain.

Thanks to whoever sent me that telepathic message:-)