NIC eth# keeps changing

wsduvall · 03-04-2009, 04:46 PM

Hey guys,

I've got a RAID server with three NIC's in them (two gigabit and one on-board). When I first installed Linux, the card I was using was eth0. Then I rebooted, and it was eth1 and then eth2. I know this has something to do with how the modules are loaded. Anybody know how to fix this? The machine is running Arch Linux.

stress_junkie · 03-04-2009, 07:04 PM

My PCLOS system has the following lines in /etc/udev/rules.d/61-net_config.rules

Code:

# grep -H eth rules.d/*
rules.d/61-net_config.rules:SUBSYSTEM=="net", ACTION=="add", ENV{INTERFACE}!="*.*", SYSFS{address}=="00:09:5b:bb:f1:ed", NAME="eth0", ENV{MDV_CONFIGURED}="yes"
rules.d/61-net_config.rules:SUBSYSTEM=="net", ACTION=="add", ENV{INTERFACE}!="*.*", SYSFS{address}=="00:0f:b5:8d:cb:2f", NAME="eth1", ENV{MDV_CONFIGURED}="yes"
#

It looks like it is assigning the eth number by the hardware address of the card.

farslayer · 03-05-2009, 07:28 AM

some nvidia chipset motherboards also had a BIOS option to change the MAC address of the on board NICs at every boot. that would be another thing to check. the MAC changing would add new rules to the file stress_junkie posted at every boot, as it automatically created a new rule to match the new MAC address..

If this is your issue, check in the BIOS for some 'security / anonymity' setting for the NIC

http://www.reactivated.net/writing_udev_rules.html

wsduvall · 03-05-2009, 09:57 AM

Alright thanks guys! I'm going to try the udev rules when I get out of class, and may post further questions.

Looks like changing the udev rules fixed the problem. Thanks guys!