How to assign IP to network interface command line in linux

This article objective is provide you the way to assign the IP address to the network interface from the command line.

You can see the available network interfaces on your machine by using the simple command ifconfig

You can find the interfaces and their names and you can identify the name which is  preceded by colon(:) in the left side. Something like eth0, lo and wlan0 etc.  The network interface lo interface is the special interface where we called it as localhost and special IP assigned to it 127.0.0.1 also called loopback IP.

Do you know? you can assign multiple IPs to single network interface. This is pretty useful when you need multiple IP addresses but you have only one network card.

We created new interface alias with IP assigned. We can do it simply by giving colon(:) and alias number.

Assign IP using ifconfig

This command will assign the specified IP to the give network interface. It is not a persistent change. The would change after reboot.

 

Get IP using dhclient

The program dhclient will get you the IP to the given interface using the Dynamic Host Configuration Protocol (DHCP). The IP which will be assigned to the given network interface which will be provided by gateway or router. If you won’t have any preference of having specific IP assigned to the network card, this can be used

 

Assign static IP

The IP we assigned above is not a persistent or static IP. Means you will lose that IP and will get an other different IP assigned after reboot. To make this IP permanent we have to edit the configuration files.

Ubuntu /etc/network/interfaces

 

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

Unlike the distribution Debian, CentOS maintains the configuration in a separate file for each interface. The  file path would be something like  /etc/sysconfig/network-scripts/ifcfg-<interface_name>.