HowTo: Add Additional IPs

How to add multiple IPs on an Ethernet network interface card i.e. eth0? OR

How to add additional IPs on a Linux server?

People find it rather hard to add the IPs manually on a Plain server. Following are the steps you can follow to add a range of IPs on a CentOS server:

1 ) Change directory to /etc/sysconfig/network-scripts/ using the ‘cd’ command:

cd /etc/sysconfig/network-scripts/ (this directory contains Interface configuration files)

2) Create a file ifcfg-eth0-range0 using your favorite text editor like ‘pico’

pico ifcfg-eth0-range0

3) Add the following lines to the file:

IPADDR_START=1.1.1.10
IPADDR_END=1.1.1.20
CLONENUM_START=1

where,

IPADDR_START is the first IP in the range.
IPADDR_END is the last IP in the range.
CLONENUM_START=1, where 1 will start adding IPs from eth0:1

4) Save and exit the file.

5) You now need to execute “ifup-aliases” script for the range of IPs to take affect. Execute the following command:

./ifup-aliases eth0

This will add the IPs on eth0 and will bring all the virtual interfaces up. You can view all the interfaces using the “ifconfig” command.