@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 :-)

 

 

  @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 wan1 of the second one.

 

Maybe, it only gets visible if physically connected? Please, if got time, name me the options menu to wuden my knowledge 😁

 

But under the line: best would be get rid of the Fortigate and use only one er605. It is already out of warranty and gets no antivirus Updates anymore and it is so f* complicated with new firmware and that new SDWAN thingy. I feel like an idiot already although I have dealt with this stuff for over 25 years and was able to do all my networking and computer stuff for 10 work places.

  @Steffffi 

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

 

oh, the normal port forwarding.. thx, of course, this one I know. So, now, it will all come down to try that physically when time. Will report back if working. Thx for your efforts!