But the floor in your thinking is that you will also prevent the people who youwant to use the site from entering.
As I said, there are many different reasons why people use proxyâs not just the reason you have outlined (to bypass a ban etc).
All that will happen is that you end up with the same problems that companies like spamhaus cause, they block so called spam ip addresses but are always at least 1 step behind the spammers and then normally prevent legitimate people from sending email and block their ip address just because it is from the same range of addresses, even though they had nothing to do with it!!!
As I said, it is a futile attempt - in actual fact I think you posted more to try and scare either the spammers or those using proxies and multiple log onâs, because it has little chance of working.
Last night I had the choice of at least 500 different ip addresses I could have used, this morning I have a similar number to choose from, these change on a daily basis, so very rarely will there be an overlap of ip address, I use firefox as a browser and have an extension that allows me to use the proxy or change it with the click of a button in the browser window - very easy, I can even tell what address I am posting from (this is being made from my own ip address not a masked one), these proxyâ s are not big servers, they are just normal users who allow pass through on their systems, there is not a hope in hell that you will be able to block all these ip addresses, so thats why you are either mis informed on the effectiveness of it or you are using it as a scare tactic.
As for if you decided to block web based email like hotmail etc you will be blocking a lot of members, and to be honest most spammers do not use these types of emails, they hijack/impersonate legitimate domains. And if people really ant to use multiple log ons that is easy, personally I have more then 6 domains registerd and can have unlimited email addresses at them all, this would leave you with a lot of work to do if I should so choose to play silly games, and I am fairly sure I would be one step ahead most of the way - thats not being big headed, thatâs just the nature of this type of thing, you can only ban once you know where they are, and you cant do that till they have posted!!!
Just making more work for yourselves without achieving your goals.