---
title: "A German ISP tampered with their DNS - specifically to sabotage my website"
url: https://daily.dev/posts/a-german-isp-tampered-with-their-dns---specifically-to-sabotage-my-website-zfuafqntl
source_url: https://lina.sh/blog/telefonica-sabotages-me
type: article
source: "Hacker News"
published: 2025-08-24T11:21:32.117Z
updated: 2026-03-15T02:27:56.487Z
tags: ["dns", "networking", "privacy", "security"]
reading_time: 4
upvotes: 86
comments: 7
language: en
---

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# A German ISP tampered with their DNS - specifically to sabotage my website

**[Hacker News](https://daily.dev/sources/hn)** · 4 min read · 86 upvotes · 7 comments

## Summary

A German developer created a website to expose blocked domains by the CUII (Copyright Clearinghouse for the Internet), a private organization that decides what websites German ISPs should block. After publishing an article about CUII's mistakes, Telefonica (o2's parent company) modified their DNS blocking mechanism, making it harder to detect blocked domains. The timing suggests this was done specifically to sabotage the transparency tool, as Telefonica first tested their own domain on the website, then changed their blocking method two hours later.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://lina.sh/blog/telefonica-sabotages-me>

## Community discussion

Top comments from developers on daily.dev.

**@akkitto** · 7 upvotes

> This is utterly unacceptable. This must become more public.

**@thraizz** · 6 upvotes

> this now redirects to a chinese website for me in germany :D

**@digeomel** · 5 upvotes

> When I lived in Germany I was pissed off at GEMA, I cannot believe that Germans put up with such $h1t. For those who don't know, and I'm not sure if this is still the case, in Germany you cannot watch legitimate videos published by the original artists on their Youtube channels or other websites, unless said artists have paid some sort of copyright fees to this GEMA organisation, which is supposed to protect the artist rights (!).
> You can read more about it here:
> https://en.wikipedia.org/wiki/Blocking_of_YouTube_videos_in_Germany

**@traustitj** · 2 upvotes

> The sad part is how easy it is to get around this, just use the google dns 8.8.8.8 or 1.1.1.1 (not google), and you by pass any such rule.

**@tsumanu** · 0 upvotes

> I have a question, what was in the website blau-sicherheit.info? In my county it's flagged was malicious

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---

Tags: [#dns](https://daily.dev/tags/dns), [#networking](https://daily.dev/tags/networking), [#privacy](https://daily.dev/tags/privacy), [#security](https://daily.dev/tags/security)

[View this post on daily.dev](https://daily.dev/posts/a-german-isp-tampered-with-their-dns---specifically-to-sabotage-my-website-zfuafqntl)