How To Reassign a Static ip address with dnsmasq

On your router you can assign static ip addresses for various machines in your network, by writing the reservations in the file /etc/dnsmasq.conf.

These will be in the form as below.

dhcp-host=<mac address>,<ip address>

So here's how you transfer an existing static ip address assignment to a new client machine. Begin by editting the file /etc/dnsmasq.conf on your router, and update the mac address associated with the intended ip address.

Next, temporarily stop dnsmasq.

systemctl stop dnsmasq

Next shutdown networking on the new client machine. Shutting the machine down might work, or the command dhclient -v -r might get the job done (you will lose the connection).

Now on the router, edit the file /var/lib/misc/dnsmasq.leases, and delete the pre-existing lease for the old client machine that will no longer exist.

Restart dnsmasq on the router,
and then restart networking on the new client machine.