I'll try and make this as clear as I can. Please tell me if I leave stuff out. Ok, my setup is like this: Fiber Modem (PPoE) -> D-Link DGS-2205 switch (port 1)->PC (port 2)-> D-Link DIR-655 (1)-> HTPC (2)-> PS3 (3) -> TV (4) -> A/V Receiver. All are wired connections. All devices have internet access. Both PCs are running Win7 Ult-64. So far I have been unable to gain access to the other PC's files from either PC. The reason I have the switch 1st is because my walls are concrete and I need the wireless to be near where I use my iPod the most. Is there a reason why I cannot share files between PCs with this configuration? And if not, how do I get it to work?
The modem is one I doubt you've ever heard of. I live in Japan. It's an NTT GE-ONU. I don't believe the problem is the modem since all devices have internet access. If I used another router instead of a switch, would that allow file sharing between the PCs?
So it's basically a fibre ONT according to what I can find about it (Japanese is rusty at best). That wouldn't work, you would simply have to have the router in front of all devices. I don't quite understand why you have the modem->switch (and PC)->router->PC's. The issue you are having is that by default the router firewalls traffic from the "outside" as well as NATing (translating one to many) the IPs.
Is there a way to make the router grant access to the switch (recognize it as being part of the local network)?
To clarify what I mentioned in my first post, the router needs to be in a separate room from my modem for my wifi to work where I need it to work. I don't want to run multiple wires across my apartment either. Is there a way to make it work as configured, and if not, what are my other options?
It would fix your security problems for the PC in front of the router, but you still would not be able to access the PC's behind the original router unless you disabled NAT (not sure if you can even do that on that model) and disabled the firewall.