Within AURO, you can create your own custom internal network and router. In case you would like to use a different fixed IP subnet than what is provided by default.
In the Auro Panel, go to Network > Router. From here add a new router, and name it as you wish.
Once complete click on "Set Gateway" to the right of the router, and add it to the external network (ext-net).
Next go to Networks > Create Network.
From here name your network, leave the state as UP, and on the next page name your subnet, and input your internal network IP space. A common internal network is 10.10.1.0/24. Set the gateway to 10.10.1.1 and click next.
From here, ensure the DHCP option is enabled, and input 18.104.22.168 in DNS Name Servers.
Finally, go back to the router and click on the router name. You can then click on "add interface" on this page and add your internal network to this router as well.
Once complete, you will be able to spawn your instances on this network, which will attach an internal IP from 10.10.1.x, and you will be able to attach a floating IP as well.