Hello Everyone,
this post here provides just some information to other users who try to get pihole working with fritzbox and DNS redirect. We struggled like two days to find the issue, that can't be solved.
We tested pihole and it works absolutely fine. Sometimes the traffic is a bit slower than without pihole, but thats not a big issue. I like to help people in Germany who happen to often have a router from avm, a fritzbox. As already mentioned in some posts here, the fritzbox has some issues with DNS settings. If you use ipv6 changing the dns server won't work correct due to some rebind protection. For more info please read this article:
You could acctually change this behaviour, but only if you are able to connect via telnet. We tried it, but our provider as most ISPs has prohibited this function. Our provider is able to update the fritzbox and change some settings, what seems to be important for the fiber connection.
You can use pihole, but have to change the DNS settings on each machine you are using. Therefore some mobile devices won't use pihole. That is kinda sad, but it is like it is. I'm talking about IPv6 only. Most connections from analytics are using IPv6.
I hope someone found this, before he got into an endless testing phase.
Cheers
Jochen