These sites were blocked because pASSword was a "bad word." The filter would also catch most queries that would tell you how to circumvent the filters. (Back then, just using HTTPS versions of sites was usually enough to get past them.)
The best part was: while searching about proxies / changing proxy settings was disallowed -- the computers themselves were dumb terminals that could connect to a remote server using VNC, RDP, and some proprietary Citrix protocol.
If you knew how to switch TTYs on Linux (Ctrl+Alt+1-7) you could get to a debug menu where you could enter any IP and protocol combination you wanted. (TTY2 had a root shell running busybox... the machines were imaged each time you booted though.)
For my last two years I simply connected to my home machine running VNC and browsed the Internet completely unfettered. (Plus I could remotely control my machine: so many times I would start long running downloads at the beginning of the school day.)
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Back then, though, these filters were laughably naive. I'm amazed that it was deemed acceptable to use a system that has to be _overridden_ for students to research for their science classes.
Of course, this effect wasn't intended, and I doubt the teachers knew about it (AFAIK nobody told them, and even if they had, I doubt the message would've been understood).
I think the reason they do it is liability: The school wants to be able to tell parents that they made commercially reasonable efforts to ensure their kids weren't exposed to inappropriate materials in school.
> It's crazy that people are ok with it.
Not really. A school library wouldn't have hard-copy Playboy magazines for students to peruse. Choosing not to allow access to the online equivalent isn't that much of a step. Parents who trust their kids with uncensored Internet access can still provide it at home.
That was the most interesting part for me. It's crazy that people are ok with it.