I have installed Centos 6 on a server with two NICs. It so happens that the NIC with the lower ARP adr is assigned 'eth1' and the NIC with the higher ARP 'eth0'. (Not sure if this a bug but it is at least inconvenient)

I have modified the udev rules in /etc/udev/rules.d/70-persistent-net.rules by swapping eth0 with eth1 in the NIC's rules.

However: the file gets changed on reboot. A third rule is automaticaly added for some reason, for one of the NICs which already has a rule. See below. The system ends up with no network interface set up at all, because the init-script gets confused.

So.... How do you specifiy the order in which NICs are enumerated? or at least how to tell centos to stop messing with the 70-persistent-net.rules?

Regards .....Volker

Contents of /etc/udev/rules.d/70-persistent-net.rules (arps anonymized):

(These are the two rules modified by me, assigning eth0/eth1 in ascending arp order)

# PCI device 0x8086:0x10d3 (e1000e) (custom name provided by external tool) SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="xx:xx:xx:xx:8f:ea", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

# PCI device 0x8086:0x1502 (e1000e) (custom name provided by external tool) SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="xx:xx:xx:xx:8f:eb", ATTR{type}=="1", KERNEL=="eth*", NAME="eth1"

(This is the rule which gets automaticaly added on reboot)

# PCI device 0x8086:0x1502 (e1000e) (custom name provided by external tool) SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="xx:xx:xx:xx:8f:eb", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"