setup eth0/apt-cdrom add

1./etc/network/interfaces

# The loopback network interface
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 192.168.1.138
netmask 255.255.255.0
#broadcast 192.168.1.255
gateway 192.168.1.1

2.apt-cdrom add

3.apt-get install pppoe;pppoeconf

4.if the device eth0 change its name like this :eth0,eth1,eth2,,,, then edit '/etc/udev/rules.d/....persistent-net.rules