I'm got two identical HP DL140 machines, both with additional Intel
Dual Port 1000/PT cards.
On the one machine (router 1)
Onboard NIC 1 = eth0
Onboard NIC 2 = eth1
Intel NIC 1 = eth2
Intel NIC 2 - eth3
On the 2nd machine (router 2)
Onboard NIC 1 = eth2
Onboard NIC 2 = eth3
Intel NIC 1 = eth0
It's just the order they were initially discovered by the system, and
it can vary.
It's also one of the reasons there's the hw-id parameter in the
interfaces section -
that way the interface your prefer is locked to an interface name. If
you want to
change the order, change the hw-id entry,
