Hi,
here is a simple way to setup dual ip in your ubuntu system if you already have eth0 as 192.168.0.10 then if you want 192.168.1.10 then use the following command to bring up a alias but this is temporary
sudo ifconfig eth0:0 192.168.1.11 up
To have a permanent dual ip update the /etc/network/interfaces file like the below
gksudo gedit /etc/network/interfaces
andadd the following content to the end of the file
auto eth0:0
iface eth0:0 inet static
address 192.168.1.10
netmask 255.255.255.0
broadcast 192.168.1.255
network 192.168.1.0
Save the file and restart system or restart the network using the following command
sudo /etc/init.d/networking restart