How to Add an IP Address to an Interface With Red Hat or CentOS Or Linux OS?

Purpose: Adding an IP Address to an Interface With Red Hat and CentOS

This tutorial demonstrates how to bind multiple IP addresses to a single network card. By using multiple IP’s you can run a service under a specific IP while having another service under a different one (for example, have HTTP on one and SMTP on another), or create a private LAN using a local IP and have the alias hold your Internet IP (such as NAT). One of the major benefits is that you don’t need a physical adapter for each IP but instead can create many virtual ones tied to a single physical card. The instructions provided apply to RedHat, Fedora, and CentOS. I’ll be using LAN IP’s in this example, so replace them with the ones you’ll be using.

The network scripts are located in /etc/sysconfig/network-scripts/

#> cd /etc/sysconfig/network-scripts/

#> ifconfig

you will see

#> cp ifcfg-eth0 ifcfg-eth0:0

vi ifcfg-eth0:0

Then type
#> service network restart

#> ifconfig

Please notice filename format: IT IS MANDATORY! Each of these files will provide IP information for a network initializing script.To activate new IPs you can reboot the server. Restart the network config activate new IPs by running one of the following scripts below:
Option 1: (Start each ip individually)

Option2: (Restart the entire network)

You are done. It is permanently added in your system. Tested both CentOS and Redhat systems.

Similarly, you can add more ips like this and repeating the steps above

cp ifcfg-eth0 ifcfg-eth0:1
cp ifcfg-eth0 ifcfg-eth0:2