Proxy by-pass

I’m a very part time Network Admin of a small high school. We use CensorNet as our web content filtering server. Students are able to by-pass CN by logging into the hundreds of free Internet based proxies like this one. http://www.daveproxy.co.uk/

I’ve talked to the folks at CN and their subscription based service does have proxies black listed but even they admitted there?re new proxies added daily.

What’s a Network Admin to do?

I have talked to the HS director about better classroom supervision but would like to know what other options are available.

Steven