This is a follow up to my 'The trouble with NAT' post. I thought I should explain the other aspect to the thread that surfaced as it progressed as it touch on some other very interesting (and apparently controversial) points of view. As I previously explained the original poster of the thread had hit a brick wall in attempting to access a website. If you want to know the full details of why and how you really should read my previous blog entry. If not then read on.
After a while a possible solution emerged to the IP ban. Use an anonymous proxy. There is however a catch with that. Most educational institutions use web filtering software to block certain categories of websites. There's the usual obvious stuff like porn, warez, gambling etc. But most also attempt to block sites that have Trojans/viruses and most relevant for our situation sites that allow users to bypass the filtering. The vast majority of these only filter based on the sites domain or the URL.
This is hopelessly inflexible. Your fighting a losing battle trying to keep up with all the new sites going up on a daily basis. No, a much more sensible and proven method is to filter based on the content of the actual web pages. This how your virus scanner and spam filter works after all! To that end I use a web filter called DansGuardian. It does domain, URL and content filtering plus it can scan for viruses.
However it seems quite a few schools are using inferior systems (and paying for them to boot!). This got me into a little trouble and a few flames. When I pointed out that the original poster could setup a simple PHPProxy based system that would solve his problem my post was moderated. Now as far I'm concerned there really isn't any point.
Not withstanding the fact PHPProxy had been mentioned previously to illustrate exactly the problems I've outlined. I feel that the tools themselves are not to blame. There always will be someone out there who wishes to take freely available information and do something harmful or illicit on their work/school/college network. You just have to prepare your systems as secure as possible and have monitoring systems in place to catch them. Assuming you do then hope your AUP is sufficient to deal with them when you catch them.