edit file: /etc/network/interfaces
the original content should be something like:
# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.0.5
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
gateway 192.168.0.1
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 192.168.0.1
add the following settings in the file:
auto eth0:1
iface eth0:1 inet static
address 192.168.0.6
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
gateway 192.168.0.1
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 192.168.0.1
run command in root mode:
/etc/init.d/networking restart
that's all. you can run ifconfig to check if it works.
I tested it in ubuntu 6.10.