I am trying to figure out a way to determine if there are any sockets listing on any ports. For example, I have a server that creates a socket, before I start listing, I want to check to see if this port is already in use, are the any system call that allow me to get that information? This should be simple, but i have not been abel to figure this out.... I am using vb.net.

open a socket and send a message on the port you want to check. if it's one of the well known ports, you'llknow what message to send (for example on 80 you can send a "get" message).

if you get a reply, you'll know that an app listens on that port. if youyou get an exception, you'll know that the port is closed.

Later edit: http://www.geekpedia.com/tutorial142_Creating-a-Port-Scanner-with-Csharp.html