How to Block Google DNS on Fritz Box

1. Make sure your DNS is set to the Unlocator DNS 185.37.37.37 and 185.37.39.39. Follow the Fritz Box Guide here you are in doubt.
2. Scroll down to „Ansicht: Standard“ change it with a click to „Ansicht: Erweitert“
   
3. Then go to: „Heimnetz“ -> „Netzwerk“ -> „Netzwerkeinstellungen“ -> „IPv4-Routen“4. Then click at „neue IPv4-Route“. Add following:
   IPv4-Netzwerk: 8.8.8.8
   Subnetzmaske: 255.255.255.255 (also try 255.255.255.252)
   Gateway: your Fritzbox local IP + 1 (e.g. 192.168.178.1 + 1 =192.168.178.2)
   
4. Check IPv4-Route aktiv and press OK.
5. Repeat this with following:
   IPv4-Netzwerk: 8.8.4.4
   Subnetzmaske: 255.255.255.255
   Gateway: 192.168.178.2
   
   IPv4-Netzwerk: 208.67.222.222
   Subnetzmaske: 255.255.255.255
   Gateway: 192.168.178.2
   
   IPv4-Netzwerk: 209.244.0.0
   Subnetzmaske: 255.255.255.248 (!)
   Gateway: 192.168.178.2
   
6. When you added all 4 IPs press OK.
7. Restart your Router and enjoy your unlocatored Chromecast.