I am currently trying to setup a pihole for my network using docker and IPv6 and I am facing some problems I could not yet find a solution to. In order to avoid additional complexity I am currently trying to get the network stuff right, before trying the installation of pi hole.
I managed to get docker on the raspi running without to much hassle using Prefix-Delegation to get a /62 Network assigned to my raspi. I instructed docker to use a /64 of this prefix for its default network (maybe later I will try using additional user defined networks to).
Using this I manged to get a basic docker container running which is reachable within the network by the global IPv6 (2001:xxxx....).
As I want to avoid the chicke / egg problem I now want to use ULA (unique local address) within the network. Therefore I setup my router (Fritzbox) to always provide ULAs no matter if there is an existing Internet-Connection or not.
This works quite well, all devices get a IPv6 address from fd00:xxxx:xxxx:0000::/64 as configured.
As I did not find a possibility to configure prefix delegation for ULA (I doubt this would be useful) there is no chance to use this mechanism to delegate a part of the prefix to use in docker.
So for now I tried to set up a a different subnet for docker like fd00:xxxx:xxxx:0001::/64 Running containers will get an address from this range and I am able to ping the address from the raspi and reach the docker interface on the raspi from within a container.
However I am currently struggling to get Routing within the fritzbox set up right. I entered the prefix fd00:xxxx:xxxx:0001/64 as a static route and put in the link-local address of the raspi (fe80:yyyy:yyyy:....)
However I am not able to establish a connection either from within a docker container towards a machine in the local network or the other way round.
Has someone got something like this working or am I just missing a crucial step/setting?