Network IP aliasing

Assign more than one IP address to one ethernet card:

ifconfig eth0 XXX.XXX.XXX.XXX netmask 255.255.255.0 broadcast XXX.XXX.XXX.255
ifconfig eth0:0 192.168.10.12 netmask 255.255.255.0 broadcast 192.168.10.255
ifconfig eth0:1 192.168.10.14 netmask 255.255.255.0 broadcast 192.168.10.255

route add -host XXX.XXX.XXX.XXX dev eth0
route add -host 192.168.10.12 dev eth0
route add -host 192.168.10.14 dev eth0
In this example 0 and 1 are aliases in addition to the regular eth0. The result of the ifconfig command:
eth0 Link encap:Ethernet HWaddr 00:10:4C:25:7A:3F
inet addr:XXX.XXX.XXX.XXX Bcast:XXX.XXX.XXX.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:14218 errors:0 dropped:0 overruns:0 frame:0
TX packets:1362 errors:0 dropped:0 overruns:0 carrier:0
collisions:1 txqueuelen:100
Interrupt:5 Base address:0xe400

eth0:0 Link encap:Ethernet HWaddr 00:10:4C:25:7A:3F
inet addr:192.168.10.12 Bcast:192.168.10.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
Interrupt:5 Base address:0xe400

eth0:1 Link encap:Ethernet HWaddr 00:10:4C:25:7A:3F
inet addr:192.168.10.14 Bcast:192.168.10.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
Interrupt:5 Base address:0xe400

Config file: /etc/sysconfig/network-scripts/ifcfg-eth0:0

DEVICE=eth0:0
ONBOOT=yes
BOOTPROTO=static
BROADCAST=192.168.10.255
IPADDR=192.168.10.12
NETMASK=255.255.255.0
NETWORK=192.168.10.0
ONBOOT=yes
Aliases can also be shut down independently. i.e.: ifdown eth0:0
The option during kernel compile is: CONFIG_IP_ALIAS=y

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