Does anyone know how to ping a proxy's ports to find an open port ?

Does anyone know how to ping a proxy's ports to find an open port ?

I need to design a quick and dirty app to ping every port on a proxy to find any available ports that are open.

Has anyone delt with this before or have any good Ideas.

I hope this will help you, if only a little bit :
http://www.mvps.org/vbnet/code/network/ping.htm

Surgeon