Hi there and thank you for contacting JustAnswer. My name is XXXXX XXXXX I'd be glad to assist you.
Check out this page for a walkthrough (with pictures) on how to port forward RDP (Remote Desktop Protocol) using your ZyXEL router: http://portforward.com/english/routers/port_forwarding/ZyXEL/PK5000Z/Remote_Desktop.htm
It's a good link, but I am still not clear on the IP address. I lease a single static IP address which is assigned to the router. Do I assign that address in the port forwarding or the LAN address of my desktop computer
It would be the LAN address of your computer.
Have tried that, but I cannot ping my router from outside the network - this seems to be the real issue
Do you need help finding the IP address of your computer
Most routers/firewalls do NOT respond to ping requests.
This is for privacy reasons.
I can figure out the ip address of my computer, but RDA still says "cannot connect" How can I test connectivity if I cannot ping the router
Your router might be able to port forward the ping requests. Let me check.
Doesn't look like it.
Then I am still stuck
Did you forward both 3389 TCP and 3389 UDP?
You can run this utility to test if the port is open: http://portforward.com/help/portcheck.htm
I will try
I have forwarded both TCP and UDP. for TCP Port checker says that 3389 is locked and that I should close any application using that - not dure what that means. For UDPit says the port is not open or not reachable
Sounds like you are either not forwarding to the correct IP or you have more than one rule for the same port.
I don't know what I did but I got it working and your links were very helpful