給網卡eth0指定多個ip，一個爲內網ip，一個爲外網ip。具體操作如下：
[root@localhost network-scripts]# cp ifcfg-eth0 ifcfg-eth0:1
[root@localhost network-scripts]# vim ifcfg-eth0:1
# Intel Corporation 82540EM Gigabit Ethernet Controller
DEVICE=eth0:1
BOOTPROTO=none
ONBOOT=yes
HWADDR=08:00:27:c5:df:40
NETMASK=255.255.252.0
IPADDR=172.16.0.232
GATEWAY=172.16.0.1
TYPE=Ethernet
USERCTL=no
IPV6INIT=no
PEERDNS=yes
