Posted 8/2/2020 17:35 (#8411266 - in reply to #8410639) Subject: Turn off DHCP and you're fine
The old router has all the switching capabilities built in. All you should need to do is turn OFF the DHCP server in the old router. Any network should only have one DHCP server on it - unless you have white tape on the nose piece of your plastic rimmed glasses and a pocket protector with a slide-rule in it.
help on converting an old modem router into a switch/Acces point
