ubuntu 14.04 lts server eth0 and eth1 are missing virtualbox

1)
Goto following file and add eth0 and eth1
sudo vim /etc/network/interfaces

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet dhcp

auto eth1
iface eth1 inet dhcp

2)
Reboot
#sudo reboot

3)
#ifconfig