To add a secondary IP to CentOSnavigate to your /etc/sysconfig/network-scripts
# cd /etc/sysconfig/network-scripts
[/bash]
# ls -la -rw-r--r--. 1 root root 203 Dec 30 14:18 ifcfg-eth0 -rw-r--r--. 1 root root 230 Dec 30 14:59 ifcfg-eth1
The system has a public and primary IP.
# nano ifcfg-eth0
[/bash]
DEVICE=eth0 HWADDR=00:0C:29:E7:7D:05 TYPE=Ethernet UUID=b9cbc9ab-d4a5-4ca8-9e3c-176c62102adc ONBOOT=yes NM_CONTROLLED=no BOOTPROTO=static IPADDR=216.55.000.000 GATEWAY=216.55.169.1 NETMASK=255.255.255.0
To add a public IP, create new files with ifcfg-eth0:1, ifcfg-eth0:2, etc