German ISP Changes DNS After Website Exposes Copyright Blocking Organization

A major German ISP altered its DNS settings after the exposure of the CUII, a private organization deciding website blocks without transparency or judicial oversight. The author built cuiiliste.de to track blocked domains, as the CUII refuses to publish its list. The CUII previously mistakenly blocked defunct websites. ISPs initially used notice.cuii.info to indicate blocked sites, but later stopped, making blocked sites appear nonexistent. However, Telefonica (parent of o2, Germany's fourth-largest ISP) continued this method. After Telefonica checked its own test domain, blau-sicherheit.info, on the author's site, they changed their DNS to stop using notice.cuii.info, making tracking CUII blocks harder. This raises suspicions of the CUII trying to bury its mistakes.