Hello, I am basically develop a business website script with some services offer (say text to image conversion) to visitors (guests), free members and subscribed premium users. Taking example of 'text to image converter' I want the limit the service offered (text to image converted) for visitors, free users and subscribed users. I have no issue in issue Free specific amount of trials for free registered users but what about providing free trials to Visitors / Guests. Basically the problem is not with static ip users, but with dynamic IP users or VPN Users. For static users, it's similar way as the free user limitation will work. Question : Does anyone here know a way to limit the text to image service to visitors (Non-signed up users) who have dynamic iPs? I've seen that in when a particular IP is banned from a server, that IP is not allowed to access it anytime, the site dosen't open even if the user uses dynamic IP but works with VPN. So, even if not VPN, i would like to have a solution to work on this. Does a computer have a System ID or System Model uniquely created which can be compared? Help is appreciated. If anyone has suggestions or tips, Post your algorithm here.