Steffffi wrote @MR.S I will take a further look at it at the weekend, but did not find that option yet in the web interface of the er605 1, the one with the Internet, to port, for example, lan4 to...

@Steffffi I don't have any routers in stand alone, but I found a simulator, here you port forward the wireguard port

@Steffffi Here is a config for a similar solution. the router is connected to the LAN with only the WAN port you get to test and play a bit and you'll probably figure it out :-)

@Steffffi You probably have port NAT on fortigate :-) you NAT the wireguard port on the first ER605 to the second ER605 WAN interface so that you can reach it from the internet.

@Steffffi because you are routing back to the LAN with this configuration. AllowedIPs = 0.0.0.0/1, 128.0.0.0/1 or AllowedIPs = 0.0.0.0/0 so you have to connect like this internett ---- WAN first...

@Steffffi no, the tp-link routers are not switches, but as I see it, you only need to connect to the WAN on the ER605. I have some similar solutions with other manufacturers and there I have only...