"Before you can remotely connect to your computer from another
location over the Internet you must properly configure your router.
The router acts as an distributor for your network traffic. If you
don't tell your router where to forward the remote desktop traffic,
it won't do anything and your remote connections won't work. Thus
you must create a port forward or virtual server entry for the
appropriate ports to the IP address of the desired computer. Then
when incoming traffic on those ports comes from the Internet, your
router will forward it onto the computer and the remote desktop
server will response. Depending upon the protocol, use one of the
following ports (or port ranges):
"RDP uses TCP port 3389
VNC uses TCP port 5900+ (Each remote connection to a server uses a
different port; display 1 uses 5901, display 2 uses 5902, etc) It's
best to define a port range when creating the forward or virtual
server entry, such as 5900 - 5905."