Where are the DHCP/Alias mappings stored?

Hi guys, I am trying to find the file located on the router filesystem that contains all the mac addresses, IPs, and custom aliases I have given to all the devices (connected and not), so I can back it up.
Example, my home computer 192.168.1.12 mac address xx:xx name DESKTOP
I don't want to export the client list out of the GUI as I want also currently disconnected devices that have been given aliases too.

Thanks