CentOS / RedHat Network config example

To configure eth0 you must edit it's configuration file:

vi /etc/sysconfig/network-scripts/ifcfg-eth0

Static configuration example:

DEVICE=eth0
BOOTPROTO=none
ONBOOT=yes
HWADDR=06:01:78:a7:00:33
NETMASK=255.255.255.0
GATEWAY=192.168.0.254
IPADDR=192.168.0.10
TYPE=Ethernet

To use DHCP:

DEVICE=eth0
BOOTPROTO=dhcp
HWADDR=00:19:D1:2A:BA:A8
ONBOOT=yes

Reference: http://www.how2centos.com/centos-configure-network/