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

Example of a network interface configuration file:

# Hardware configuration:
UUID="46e26279-f69b-daf5-1b79-d03677b7178d"
HWADDR=00:1C:C0:0D:36:C6
DEVICE="p1p1"
TYPE="Ethernet"
ONBOOT="yes"
NAME=eth0
NM_CONTROLLED="no"

# IPv4 configuration:
BOOTPROTO="none"
IPADDR0="192.168.1.100"
PREFIX0="24"
GATEWAY0="192.168.1.1"
DNS1="192.168.1.53"
DEFROUTE="yes"
IPV4_FAILURE_FATAL="yes"

# IPv6 configuration:
IPV6INIT="yes"
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes

Parameters

BOOTPROTO
Can be set to dhcp if the interface will be automatically configured by a DHCP server, or to static if the interface will have a static IP configuration, or to none.
DEFROUTE
If set to yes, then during the activation of the interface, a default route towards the associated gateway will be added on the system.
HWADDR
The MAC Address of the interface, (HWaddr in the output of ifconfig), physically burnt on the device by the manufacturer.
NM_CONTROLLED
Whether or not the interface is controlled by the NetworkManager service. If set to no, the operation of the interface needs to be controlled elsewise, e.g. with running the network service in the place of NetworkManager.
ONBOOT
Whether or not the interface should be activated automatically during system startup.