@NeilF I haven't explored the eventual security risks on the current Deco M4 Guest network. I'm hoping that someone from TP-Link explains to us how the feature is implemented. The devices connected...

@Ed-win Thanks for the feedback. Hopefully, someone from TP-Link will clarify your findings to the peace of mind of eventually related security issues.

@Ed-win let us know what you find out from your tests. I've just run the "open ports" test with Fing and it finds none while connected to the guest network. Nevertheless, I would also prefer to omit...

@Ed-win I also have the same network architecture (Internet router -> Switch -> Deco), the devices connect to the guest network can see the devices on the main network (using Fing, for example) but...

@Ed-win I have M4R V1 with firmware 1.4.3 Build 20200918 Rel.74289, operating as Access Point.

@Ragar The application just shows the option to "Isolate From Main Network".