Sometimes can be useful to use two different IP via one ethernet card. An example:

gksudo pluma /etc/network/interfaces
… the contenst

auto lo eth0 eth0:0
iface lo inet loopback

iface eth0 inet dhcp

iface eth0:0 inet static
address 192.168.8.1
netmask 255.255.255.0

gksudo pluma /etc/NetworkManager/NetworkManager.conf
… the contents

[main]
plugins=ifupdown,keyfile,ofono
dns=dnsmasq

[ifupdown]
managed=true

Reboot