network configuration sample on Cent OS

External network interface using dhcp: /etc/sysconfig/network-script/ifcfg-eth4

[root@sr2s18 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth4 

DEVICE=eth4

HWADDR=00:26:B9:38:4C:23

TYPE=Ethernet

ONBOOT=yes

NM_CONTROLLED=yes

BOOTPROTO=dhcp

Internal network interface using static IP: /etc/sysconfig/network-script/ifcfg-eth0

[root@sr2s18 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0

HWADDR=00:1B:21:44:96:10

TYPE=Ethernet

ONBOOT=yes

NM_CONTROLLED=no

BOOTPROTO=static

IPADDR=192.168.0.38

BROADCAST=192.158.0.25

NETMASK=255.255.255.0

NAME=eth0