ok Im working on a project right now that is software that is sold on subscription basis...

so they buy the software and it can be used for a year from installation. I need a way to track this information, so I was thining of implimenting a client server type program, where we use a static IP and when users open the program, it connects to our IP via winsock to verify their subscription. This would also be useful for checking for product updates too.

The app itself collects data and submits it to a third parties website, so the computer HAS to be connected to the net for this app to work.. so that is not an issue

Our DSL carrier (Verizon) offers some business solutions including static IPs. So we could run a server and forward whatever port to my server side app when users connect. I would imagine it would only be a few hundred people who would purchase the software, and the connections to our server would be brief (only to transmit the data real quick, and then disconnect) so I don't think we would run into a bandwidth issue.

What kind of problems or limitations do you think I would encounter with this type of implimentation..