Comment Re:Does anyone use these filtered ISPs? (Score 1) 221
The NZ filter works by collecting a list of banned websites.
The websites addresses are converted to IP.
These IPs are advertised to the ISPs via BGP.
The ISPs divert all traffic for that IP to the government filter server.
The government filter server examines the request against the list of banned websites, and decides whether to forward or block. Only HTTP is examined, everything else is forwarded.
So, you can't get around it via DNS tricks.
More details: http://techliberty.org.nz/issues/internet-filtering/filtering-technical-faq/