Static IP

Distro(s): Debian and Redhat based.

Description: Configure static IP, Mask, Gateway, and DNS.

Assuming eth0 is the network interface to edit;

Debian/Ubuntu Systems if possible, bring interface down first: ifdown eth0.

1) Edit /etc/network/interfaces

nano /etc/network/interfaces

2) DHCP Setup Example (Default)

auto eth0
iface eth0 inet dhcp

3) Static Setup Example

auto eth0
iface eth0 inet static
  address 192.168.0.100
  netmask 255.255.255.0
  gateway 192.168.0.254
  dns-nameservers 8.8.8.8 8.8.4.4

4) Bring the interface up (if brought down at the start)

ifup eth0

5) Otherwise, restart to fix nameserver conflicts between dhclient and static.

shutdown -r now

Redhat/CentOS Systems

1) Edit /etc/sysconfig/network-scripts/ifcfg-eth0

vi /etc/sysconfig/network-scripts/ifcfg-eth0

2) DHCP Setup Example (Default)

DEVICE=eth0
ONBOOT=no (change to yes to have DHCP start automatically)
NM_CONTROLLED=yes
BOOTPROTO=dhcp

3) Static Setup Example

DEVICE=eth0
ONBOOT=yes
NM_CONTROLLED=yes
BOOTPROTO=static
IPADDR=192.168.0.101
NETMASK=255.255.255.0
GATEWAY=192.168.0.254

4) Edit /etc/resolv.conf

vi /etc/resolv.conf

nameserver 8.8.8.8
nameserver 8.8.4.4

5) Restart network service

/etc/init.d/network restart