CentOSの固定IP

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

DEVICE=eth0
HWADDR=00:A0:B0:A5:0D:6E
ONBOOT=yes
BOOTPROTO=dhcp
TYPE=Ethernet
USERCTL=no
IPV6INIT=no
PEERDNS=yes

DNSの値も固定にする
vi /etc/resolv.conf
search localdomain
nameserver 192.168.12.1