sudo ip link show
sudo ip link set dev eth0 down
sudo dhclient eth0
This will bring your eth0 up by using DHCP. Your network is now configured (for the time being).
If you don't have DHCP enabled configure your network by issueing the commands below, the gateway address is the IP address of your router. And your IP should be in the same range as the router is.
sudo ip addr add 192.168.1.14/24 dev eth0 sudo ip link set dev eth0 up sudo ip route add default via 192.168.1.1