sorry the snap link is case sensitive http://www.picscrazy.com/view/DXXu
As per the diagram, I’m assuming you are utilizing ACL on the routers since I don’t see a firewall in place. You may need to add a line within the ACL section with external IP to internal IP via specific ports. I’m not a Cisco guy but you should be able to google it add those lines to your Cisco router. The other option is to install a product like “logmein” which would make any system that can connect to the internet available to you.