Limiting user's based on visits or ip address

Ok, I want to setup a registration system where it limits the user to a single registration per network, or even better per computer.

I have thought about using ip address' however, at least where I come from, ip's arnt static, they are dynamic, so this could cause 2 problems, firstly a user will change ip after restarting their router and just be able to register again, and secondly someone else may end up with someones old ip who previously registered, and not be able to register.

My second idea was to use cookies, however these can obviously be removed or cleared very easily. Also are cookies shared across user-agents (browsers) or are they different for each browser?

At the moment I am considering using a mixture of the two, however im open to better suggestions.

Thanks, Josh

re: Limiting user's based on visits or ip address

track them by emails.

What you suggested is all have been tried and failed before. It's not a road you want to go down on. There's a big brick wall at the end.

The web stateless, It's made so that a single person/computer cannot be identified. (well at least the clients, servers are a different story).

There's nothing coming from my computer that you can capture and identify me with that I can't change. I can even fake MAC addresses if I wanted to.

So it all comes downs to, how bad do you want users to not register. You can make it inconvenient (using their emails) which would mean they would need to create another email address for each registration. It also depends on your application. Is it an internet or intranet app? if you block a computer at a library/public place after the first registration, do you care if nobody else can register from the computer anymore?

List your business requirements, I can advise you further.




Dan

re: Limiting user's based on visits or ip address

Well basicly im building an internet application, heavily using ajax, dhtml, ect and I want to limit a users registrations, It isnt designed to be the kind of application you would use at a netcafe or library, so thats not really an issue. I am not to worried about multiple registrations to be honest, I just want your general, average internet user to not bother trying to register twice. At the moment I am thinking I may just go with the email idea, and have cookies (just as an extra measure, I wont actually depend on these).

Thanks heaps for a solid reply, Josh