@Alexandre. Thank you for your reply and for the link provided, which is very relevant. The behaviour I'm experiencing seems consistent with a managed switch where the vlan tagging has not been set...

Confirming all units are Deco M5 hardware v3.20, running firmware 1.7.3 Build 20230906 Rel. 59213

Hi there, I'm having issues getting a Deco M5 guest network working correctly. The network topology is very simple, as follows. Deco #1 was set up first, in router mode, then Decos #2 and #3 were...