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A German ISP changed their DNS to block my website

One of Germany's biggest ISPs changed how their DNS works, right after I exposed an organization that they’re part of.

If you asked an ISP's DNS server (basically the internet's phone book) for a site and got a CNAME to notice.cuii.info, you knew it was blocked. ISPs like Telekom, 1&1 and Vodafone actually all stopped using this response a few months ago, after older articles about the CUII's past failures were published. Telefonica (the parent company of for example o2, Germany's fourth-biggest ISP), apparently didn't get this memo, and they still used notice.cuii.info in their DNS responses.

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