Adding another IP in Linux
1) goto /etc/sysconfig/network-scripts
2) copy the file that is the interface, e.g. ifcfg-eth0, rename the copy
ifcfg-eth0:1 where was is the virtuial id.
3) edit this file so the ip address is the new required address
4) save the file
5) in the same folder run 'ifup eth0:1' this should bring the new ip up
6) check by running /etc/ifconfig