CentOS – How to configure static ip address on CentOS 7

Problem

You just finished an install of CentOS 7 and need it to be networked with a static address

Solution
Verify if there is an IP address (from DHCP) using the following command

ip addr

Check the permissions on the interface config file (interface will vary ifcfg-ens101 in my case)

ls -l /etc/sysconfig/network-scripts/ifcfg-ens101

If its read only update the permissions as required

sudo chmod 777 /etc/sysconfig/network-scripts/ifcfg-ens101

Edit the interface

vi /etc/sysconfig/network-scripts/ifcfg-ens101

Edit/add the following fields

HWADDR=00:01:02:03:04:05
TYPE=Ethernet
BOOTPROTO=static
DEFROUTE=yes
PEERDNS=yes
PEERROUTES=yes
IPV4_FAILURE_FATAL=no
IPADDR=192.168.0.100
NETMASK=255.255.255.0
NM_CONTROLLED=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
IPV6_FAILURE_FATAL=no
NAME=enp0s3
UUID=abc12300-abc1-abc1-1234-abc123abc123
ONBOOT=yes

If you had updated the permissions previously, lower as per your requirements e.g.

sudo chmod 766 /etc/sysconfig/network-scripts/ifcfg-ens101

Now let’s configure the default gateway

vi /etc/sysconfig/network

Add the following or edit as required

NETWORKING=yes
HOSTNAME=MyCentOS
GATEWAY=192.168.0.1

While we are at it let’s update the DNS entries

vi /etc/resolv.conf

Use the nameserver command to add dns servers to look up e.g.

nameserver 192.168.0.2 – assuming that .2 is your internal dns
nameserver 8.8.8.8
nameserver 8.8.4.4

One more command, restart the network interfaces

/etc/init.d/network restart

Test by reviewing the interface settings

ip addr

And by issuing a ping command e.g.

ping 8.8.8.8

Tested Platform
CentOS 7

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