It is actually possible but it depends on your ISP and the type of fiber connection you have (it has to be fiber directly to your house, with a dumb “Fiber Media Converter” (ONT) that simply converts fiber to RJ45 before going into your ISP provided router).
You can then connect the RJ45 port of the media converter directly to your switch bypassing the router, then add the router in the second switch port just like any other device. From the routers perspective it will think it’s connected directly to the fiber converter.
It’s absolutely not advised because the topology is awful, but it is possible. I’ve done it when I’ve needed to dial the PPPOE fiber from both my router and my server separately and directly.
It is actually possible but it depends on your ISP and the type of fiber connection you have (it has to be fiber directly to your house, with a dumb “Fiber Media Converter” (ONT) that simply converts fiber to RJ45 before going into your ISP provided router).
You can then connect the RJ45 port of the media converter directly to your switch bypassing the router, then add the router in the second switch port just like any other device. From the routers perspective it will think it’s connected directly to the fiber converter.
It’s absolutely not advised because the topology is awful, but it is possible. I’ve done it when I’ve needed to dial the PPPOE fiber from both my router and my server separately and directly.