Binding Network Devices

Step 1

You can manually force the assignment from a network card to what device comes up as (eth0, eth1 ...), by changing the udev rules. You can manually edit this file:

           /etc/udev/rules.d/70-persistent-net.rules

This file maps MAC address to device name.

Example

SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1d:60:b5:43:66", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="5c:d9:98:af:21:43", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="et1"

This file maps the card with MAC 00:1d:60:b5:43:66 to eth0 and the card with 5c:d9:98:af:21:43 to eth1.

If you want to reverse the assignments, switch eth0 and eth1 at the end of the entries. Or delete one of the entries.

Step 2

You may need to also edit this configuration file as well:

           /etc/sysconfig/network-scripts/ifcfg-eth0

if it has the MAC address for the device in it (e.g. in a variable called HWADDR).

Example

           HWADDR=00:1d:60:b5:43:66

You will need to adjust the HWADDR to match the MAC address of the card you wish to make eth0. Note: if you wish to keep eth1 active, you may also have to edit ifcfg-ith1 as well.

These changes will only take effect after a reboot or a restart of the network services.

Please exercise care. Improperly modifying these files may render your system without network or even not boot properly.