Binding Network Devices
From Amahi Wiki
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 assignements, switch eth0 and eth1 at the end of the entries. Or delete one of the entries.
These changes will only take effect after a reboot.
Please exercise care. Improperly modifying this file may render your system without network or even not boot properly.