It may be that I'm trying to do something that's not possible, and I'm just not experienced enough with networking to realize it, but here's my situation:
Due to a lengthy series of events that aren't relevant, the D-Link router in question is being used wired-only (wireless disabled entirely) to take a DHCP WAN connection and share it to the LAN. I want to give computers on the WAN (which is actually a VLAN on a much larger campus network) file sharing access to a single computer on the internal LAN.
To this end, I set the WBR-2310 to give a static IP address to the computer in question, and to port forward ports 445 and 135-139 to it. This didn't work--trying to access the external IP address just times out. Its network name doesn't work, either.
I then tried adding the internal computer to the DMZ. Same result. I also tried forwarding ports 1-65000 for both TCP and UDP; also no luck. I also don't get any ping response from the external address, despite having ping enabled in the D-Link menus.
Now, RDC does work just fine from the outside, so port forwarding is at least partly working. And file sharing is set up properly on the computer, because when connected to the internal network, I can access the computer via SMB both using its (internal 192.*.*.*) IP address and its name. It's just when connecting from the WAN that I get no response at all.
Is there a routing issue that I'm not understanding here, or is there a checkbox somewhere that I'm missing?