On Berta D2 board the Ethernet section normally is turned-off
To turn it on wire the line EN ETHN to GND on J6 pin or wire the ENABLE ETHN to a GPIO line and control the power-on by software.
By default the Linux images available on this site gets the IP address from the local DHCP server.
This is the default configuration of eth0 lan interface saved in /etc/network/interfaces :
allow-hotplug eth0 iface eth0 inet dhcp
To set a static IP address change this section in:
allow-hotplug eth0 iface eth0 inet static address 192.168.1.90 netmask 255.255.255.0 gateway 192.168.1.1