一つのNICに２つのIPを設定する

ip -4 addr

こういうケース

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    inet 127.0.0.1/8 scope host lo
    inet 172.27.111.152/32 brd 172.27.111.152 scope global lo:0

vi /etc/sysconfig/network-scripts/ifcfg-lo:0

DEVICE=lo:0
IPADDR=172.27.111.152
NETMASK=255.255.255.255
NETWORK=172.27.111.152
BROADCAST=172.27.111.152
ONBOOT=yes
NAME=loopback-dsr

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

DEVICE=lo
IPADDR=127.0.0.1
NETMASK=255.0.0.0
NETWORK=127.0.0.0
# If you're having problems with gated making 127.0.0.0/8 a martian,
# you can change this to something else (255.255.255.255, for example)
BROADCAST=127.255.255.255
ONBOOT=yes
NAME=loopback

こちらは通常のIP設定

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    inet 172.27.111.61/24 brd 172.27.111.255 scope global eth0

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

DEVICE=eth0
BOOTPROTO=static
IPADDR=172.27.111.61
NETMASK=255.255.255.0
NETWORK=172.27.111.0
BROADCAST=172.27.111.255
NM_CONTROLLED=no
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
TYPE=Ethernet
ONBOOT=yes