I changed the fixed ip address in network/interfaces on server XYZ, and "ip addr" reflects the change. I rebooted XYZ. I am able to ssh to the system using the new IP addr (192.168.1.1) . However ...

10.1.1.2 is assigned via DHCP or manually configured on the Wi-Fi interface. 10.1.1.20 is manually configured as an IP alias on the same interface. When the Wi-Fi interface goes down (i.e. "inactive" ...