Installing Squeeze with newer kernels on servers with 4, 6 or more interfaces, I keep getting this really annoying problem: interfaces are always mixed up across cards, and don't even follow ascending hardware address order. What's going on?Typical example of 70-persistent-net.rules on a machine with 2 dual port GigE cards :# 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 0x8086:0x105e (e1000e)SUBSYSTEM==net, ACTION==add, DRIVERS==?*, ATTR{address}==68:05:ca:04:f8:5e, ATTR{dev_id}==0x0, ATTR{type}==1, KERNEL==eth*, NAME=eth0# PCI device 0x8086:0x105e (e1000e)SUBSYSTEM==net, ACTION==add, DRIVERS==?*, ATTR{address}==68:05:ca:04:f8:5f, ATTR{dev_id}==0x0, ATTR{type}==1, KERNEL==eth*, NAME=eth2# PCI device 0x8086:0x10c9 (igb)SUBSYSTEM==net, ACTION==add, DRIVERS==?*, ATTR{address}==00:25:90:72:55:71, ATTR{dev_id}==0x0, ATTR{type}==1, KERNEL==eth*, NAME=eth3# PCI device 0x8086:0x10c9 (igb)SUBSYSTEM==net, ACTION==add, DRIVERS==?*, ATTR{address}==00:25:90:72:55:70, ATTR{dev_id}==0x0, ATTR{type}==1, KERNEL==eth*, NAME=eth1I know I can change the order easily; however I must not forget doing it on all and every  server else it will cause all sorts of weird problems; it's particularly annoying when it mixes up 1 GigE and 10 GigE interfaces. 
udev randomly mixing up ethernet devices on Debian Squeeze
debian;udev
Apparently the latest squeeze upgrade (6.0.5) fixed that. So that probably was some udev bug, or udev rules generator script bug.