I have a Windows 7 PC running Serviio as a DLNA server. I have a Samsung I9100G running Skifta as a DLNA renderer (client). My network topology:

At the moment, I can connect and watch my videos fine if the phone is on router #2. The server is on a wired network with #2. Router #1 is 192.168.1.1, router #2 is 192.168.2.1 (192.168.1.2) and router #3 is 192.168.3.1 (192.168.1.3). In other words, each router has its own subnet, using NAT - their "modem" port is connected with a "LAN" port on the modem/router 1.

What I want to do is be able to connect to the DLNA server if the renderer is connected to router #1/#3 - #1 is on the WAN side of #2, while #3 is even further separated. I'll settle for just #1 working, though.

Normally, I would just forward the appropriate ports, and everything would work fine. However, (apparently) DLNA uses UPnP, which I am unfamiliar with. I tried enabling UPnP on router #2, but that did not seem not change anything. It's a Belkin F5D7230-4 6000 - there's reported issues with UPnP on F5D7230-4 7000. UPnP is already enabled on router #1 - a Billion BiPAC 7700N.

I've also tried the built in DLNA renderer/server/controller on my phone, Samsung AllShare. It can see the server on router #2 and browse files, but has issues playing or downloading them. It also can't see the server on the other two networks.

I'm currently using Skifta/s "local" mode. "Remote" mode requires an account, which I don't really want to create if not necessary.

Is it possible too do what I'm trying to do? If no, are there workarounds? If yes, how do I do it? Is my server the issue? The renderer (client)? The router(s)? My method? I can change just about anything except the routers.