What determines the assignment of eth0, eth1, eth2, etc..

larold · 02-04-2010, 12:04 PM

Apologioes but I don't have time to investigate - thought I'd ask here.

I've got five HP DL580s with a couple of onboard broadcom nics and an additional 4 intel nics that were also installed.

What determines which nic gets assigned to eth0, vs. eth1, vs. ethX. Is it consistent across servers? The data center guys connected only one NIC on each box - same port on each server. This consistently came up as eth6. (That's what I've been using for primary connectivity.)

Thanks!

(PS. Same OS. Save cards in same slots. Same hardware. Everything identical except for MAC addresses obviously)

EricTRA · 02-04-2010, 12:07 PM

Hello,

Have a look at the udev man page. The assigning is done using udev rules. My persistent net file looks like this:

Code:

cat /etc/udev/rules.d/70-persistent-net.rules
# This file was automatically generated by the //lib/udev/write_net_rules
# program, run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single
# line, and change only the value of the NAME= key.

# PCI device 0x10ec:0x8168 (r8169)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:16:d3:52:20:53", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

# PCI device 0x8086:0x4222 (iwl3945)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:19:d2:2b:42:93", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan0"

I think that's what your looking for.

Kind regards,

Eric