I'm using a Netgear R6500 router and both IDs are hard wired to it. Upnp is activated and as far as I know everything is set up properly for the router.
While the IDs see each other as controllers and can pull from each other, I'm puzzled why they don't see each other as renderers (both also have all the boxes for controller, server and renderer checked). They can see other renderers with no problem (includer jriver windows).