Is there a way to tell if an ip address if infact a proxy?

[nennii]

I run a forum, and I'm having trouble with a couple people evading their bans by proxying. Is there any solution to this?How would I go about finding out what proxy site they're using and how would I ban that ip?

[oddball]

Other than banning the proxy site, No.Due to Dynamic IP addresses, if you ban an IP address you will ban an entire ISP. That means that none of that ISP's customers can get access to your forum. If you ban the Proxy site IP address only that Proxy site and anyone using it will be blocked.

[Colinc]

Try setting up a registration system using email addresses and passwords. You can post that the email addresses are strictly confidential. Then you can block them by changing their passwords and using a blocked marker in the security data. They may try to sign themselves up again, but if you need to email a password for them to join they are dead in the water.