@MAW I understand Deco has its own method to segregate main, guest and IOT network. I believe all devices wired into the Deco are on the main network. The Deco are using a specific VLAN for the guest...

@deonholtz If the Operation Mode of the Deco is "Router" (this is the default), the Deco will, indeed, handle the DHCP functionality. If the old router was configured in a specific way to be...

@Fiordhraoi It is important that DDNS names have a short TTL, because the associated IP address can change frequently. It is strange that you get "could not be resolved" while nslookup can resolve it.

@MAW There are many different ways to setup VLANs. What do you want to achieve?

@deonholtz The message "Abnormal WAN port speed" is caused by your usage of a low speed router. The Deco is simply surprised that the router does not support an higher speed, and warns you about that...

@PierreC83 The Deco app is not always reliable, sometimes it does not show correctly the connected clients. The Deco might be different hardware versions, that would explain why they do not have the...