Mine

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback
address 127.0.0.1
netmask 255.0.0.0

# This is a list of hotpluggable network interfaces.
# They will be activated automatically by the hotplug subsystem.
auto eth0

# The primary network interface
iface eth0 inet dhcp