My computer is behind a Linksys router and cable modem. I have assigned a static IP to my computer and setup port forwarding in the router config to pass TCP and UDP ports 134-139 and 445 to my static IP. Also I have setup port 3389 to forward for remote desktop. My brother can remote desktop into my computer from his computer (same config - behind cable modem and router) and I can remote desktop to his but he can't connect to the shars that I have setup on my computer. Firewall is turned off. Do I have the wrong ports forwarded? What am I missing?
You are playing with fire opening up shares across the Internet without using a VPN! I suggest you consider setting up an FTP server if you want to share files, much more secure and easier to manage.