Debian uses udev. Udev handles mapping MAC's to the appropriate /dev/eth(X) file. If you copy a Virtual machine, Udev will remember the MAC address of the old NIC. When you copy the machine, the virtual host usually generates a new MAC address for the VM. Udev will assign …

You can find out how much bandwidth your linux machine is using with a simple tool called "bwm-ng". In Debian, install it with

aptitude install bwm-ng

Then, just type 'bwm-ng' in the command line. It will give you something like this:

bwm-ng v0.6 (probing every 5.000s …