Add a second ip to Linux / Ubuntu /etc/network/interfaces

There are situations when you want or need a second IP on your box, for example when you are installing a firewall (In this case is always better to have two NICs but you can do it with only one)

We will assume you already have a system running and already has one IP, if not you wanna read Define a static IP in Linux.

Now we will add the second IP use the same command specifying a virtual NIC