Network "Interfaces" configuration

    auto eth0
    allow-hotplug eth0
    iface eth0 inet dhcp

iface eth0 inet6 dhcp

or

iface eth0 inet6 auto

Static Configuration

   auto eth0
   iface eth0 inet static
       address 192.0.2.7/24
       gateway 192.0.2.254

dns-nameservers 12.34.56.78 12.34.56.79