Howto add a IP alias on the "green" interface in IPfire
Let’s say you have an internal /24 network and you want to add a secondary (local) IP address (this could be useful in case you remove an old machine from the network and your new firewall is on a different address - but your new firewall should offer on of it’s services on the old address).
In the ipfire GUI this is not possible. But you can use the file “rc.