Hello @Clive_A, Thank you for your answer. I'm unfortunately not allowed to merge the LAN (192.168) and the WAN (10.0) even though both are local. It is of course possible to achieve by using two...

We are using an ER605 to provide a guest network with its own IP range and DHCP server. This network is accessible via the LAN ports. The WAN port is connected to our main network (10.0.0.0/22),...