How does Ultravnc connect

[joe avarage]

I've used Ultravnc, Pchelpware and Singleclick for some time know and it works OK.

I am trying to learn about socket programming and write a little server (windows, c language). I have written a small client and small server. The client connects to 127.0.0.1 and send a "Hello world" which the server echoes. It works OK.

I am having problems with doing teh same connecting through a dynam, ie. connecting to mydyndns.com and not 127.0.0.1. My server is listening to port 5500 and the dyndns server should direct me back to home computer.

I know it should work since Ultravnc works great. When I use is it the UVNC server is listening to port 5500. I've set port forwarding on the router to the 192.168.0.100 where my server is running and listening.

So far:
127.0.0.1 works
127.0.0.1:5500 works
mydyndns.com does not work
mydyndns.com:5500 does not work

I must be missing something that UVNC does when all of above work. Can anyone give a clue?

[redge]

enable loopback on your router

[joe avarage]

I don't think that is the issue since UVNC and Pchelpware work fine without it. I tried it though - no luck.

[Aergan]

Maybe you are only listening on localhost (127.0.0.1) rather than your WAN?