Blocking another server from calling/altering the info passed to my php pages

[system]

I have programmed my own system for client info -> server check within my C++ app and my website to allow only one user, however I am sure many users have used another server to redirect the call and alter the code and then send it to my server to get around the one user per application. Is there anyway to determine if the web call was from another server?? I have included a hash within the param’s that are send with the information, but i am sure they have altered this also to make the call complete and pass my server check.

Thanks
Cjg

[astonecipher]

Is the single user you?

Have you thought about testing the IP to allow access?

[cjg9590]

IP’s change too often to lock a user by it, and no I have 1000 members which use my program.

[astonecipher]

But you said,

only one user

So whom are you actually trying to lockout if you have hundreds of users?