I have a custom application that keeps track of registered users by ip address. When they register it registers them for that ip so they do not have to register again. A small percentage of users are having to register multiple times, but the same IP address keeps showing up. I believe this to be because a small number of providers are taking single ip's and adjusting the headers each time.
I need someone to adjust the code and successfully fix the problem. About 20 people register a day. The problem will be considdered fixed when the website can go 3 consecutive days without someone having to register more than once with the same ip address, and the rest of the system will continue to work as designed.