Hmm, this well help some info I found about Dlink routers
Virtual server allows requests to certain ports from the Internet to be redirected to a specific IP on your internal network. For example: If you have a Web server (port 80) behind the firewall with an IP address of 192.168.0.32, then all requests from the Internet that access port 80 on the DI-713 will get redirected to the Web server (192.168.0.32).
The Special Applications page is used because certain applications (Dialpad, Battle.net, etc.) will not function properly behind a NAT router. D-Link has several known applications and the ports they require built into the DI-713, so all you have to do is pick the app and whether or not you want to enable the ports. They are all disabled by default. So that the hardcore gamers know, I played Quake3 and Team Fortress Classic without setting up anything special on the router and had no problems playing the games.
With Access Control, you can assign rights to different users or sets of users based on an IP address or a group of IP addresses. For example, if you have children and you do not want them accessing the web, then you can block port 80 for their machine.
The last item in the advanced configuration is the Miscellaneous Items where you can set the IP address of the DMZ (DeMilitarized Zone) and you can also limit who has access to the administration menu of the DI-713 based on IP address. NOTE: You shouldn't use the DMZ Host option unless it is needed. If you specify an IP address in this field, data will be allowed to bypass the firewall - thus allowing unrestricted access to the computer with the specified IP address.
