Configure IP Address

In CentOS 6x the IP settings are held in file(s) located in the /etc/sysconfig/network-interfaces directory, there is one file for each physical interface, they are generally called:
ifcfg-eth0
ifcfg-eth1
ifcfg-eth2
ifcfg-eth3
ifcfg-eth4
ifcfg-eth5
ifcfg-lo
To see exactly what files you have, and what they are called simply do a list

ls /etc/sysconfig/network-scripts

To edit a file enter:

vi /etc/sysconfig/network-scripts/ifcfg-eht(0) --- (use the correct eth number for your system)

Below is an example of a static ip configuration for the first NIC (ifcfg-eth0)

DEVICE="eth0"\\
BOOTPROTO=none\\
IPV6INIT=no\\
NM_CONTROLLED=no\\
ONBOOT="yes"\\
TYPE="Ethernet"\\
IPADDR=192.168.27.110\\
NETMASK=255.255.255.0\\
GATEWAY=192.168.27.254\\
PERSISTENT_DHCLIENT=yes\\
DHCP_HOSTNAME=h64.envivio.com