How to set static IP address?

To give static ip address graphically

1.Go to network connections

2.Then edit the connections in the wired settings

3.Add the ip address for the system

Here are the images below

If you are curious, You can find newly created connection from the above steps as configurations file at /etc/NetworkManager/system-connections

Edit /etc/network/interfaces to reflect something like this:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.0.X
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
gateway 192.168.0.X
dns-nameservers 192.168.0.X

Then do a:

sudo /etc/init.d/networking restart

And that will get you fixed up.