How to set static IP and set my DNS in Ubuntu Server 14.04

If you try to edit /etc/resolv.conf as most information on internet suggest, your information will be overriden after reboot. To change DNS modify file:

sudo nano /etc/resolvconf/resolv.conf.d/base

Just add the same lines like in resolv.conf:

nameserver 8.8.8.8 #ip of your DNS server

then update resolv.conf:

sudo resolvconf -u

after that /etc/resolv.conf should contain your DNS ip.

To change ip address to static edit /etc/network/interfaces:

sudo nano /etc/network/interfaces

find and comment default dhcp entry. Next add lines to your config file like below:

# 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
# DHCP not needed
# iface eth0 inet dhcp
iface eth0 inet static
address 192.168.1.99
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.168.254

then disable/enable network interface

sudo ifdown eth0 && sudo ifup eth0