BubbleUPnP server is (asking other things) an authenticated DLNA proxy, for exposing your server to the internet. It works alongside a server like readymedia, rather than replacing it. It's unfortunate, imo, since I'd love to have a DLNA server that exposed my cloud storage and media library together, like the BubbleUPnP Android app is capable of doing, but without needing to have an Android device in the mix.