| > Any request that is denied by OpenDNS is then allowed by our DNS server, and any request allowed by OpenDNS is blocked by us. The most interesting part of this to me is using multiple DNS providers to determine which category the site is in. It's both simple and effective. If they actually go ahead with this plan in the UK and it's implemented similarly (eg. via DNS rather than IP blocking), somebody should make a list of what's blocked. Go through the top N sites and for each run a DNS lookup from both a filtering DNS server and also a couple non-filtered ones (ex: Google DNS[1]) then compare the results[2]. Bonus points if someone builds a way to crowd source the data so that it gets logged from multiple DNS servers round the world. [1]: https://developers.google.com/speed/public-dns/ [2]: This would need to do more than a plain A == B as each address could resolve to multiple IP addresses. |
The current UK ISP filter (the one that already filtered Wikipedia), used DNS & HTTP. IP addresses that needed filtering were redirected to their HTTP server by sending back their IP address, and then a HTTP proxy was used to filter specific URLs. This allowed them to block certain URLs. It was initally detected because lots of wikipedians noticed a lot of edits (basically lots of the UK) coming from a small amount of IP addresses (the IP addresses of the proxies)