I'm experiencing an odd problem on my 2850, I have had problems seeing the dlna server (microserver) on both the wired connection to the main pc and the wireless to the tv.
Yesterday I reset the 2850 to factory and just did the minimal config on it, everything was fine for a few hours with the dlna service visible then it disappeared, I rebooted the router and back it came.
I waited a few hours and sure enough the service disappeared, just to check I popped a hub in the circuit so the devices were connected outside the 2850 and the pc could see the server ok instantly, restored the connections and rebooted the 2850 and sure enough the dlna device was visible again.

It doesn't affect windows networking the microserver is always visible and I can remote into it but the dlna media devices drop out of the networking window and the tv cannot see them either, I have tried both plex and servio. I'm 100% sure its the 2850 and its on the latest firmware, upnp and igmp settings have no effect on the disappearance. If I plug in my old 2820 everything just works as it should.

Is there a setting or configuration I have maybe missed?

Paul