This is really a request for more information is this is a known issue or anyone knows of similar problems.
I have an Rpi4 with pihole, wireguard and, more recently, Homebridge installed. Pihole is my DHCP server and IPv6 is enabled. My network is dual stack IPv4 and IPv6. Everything runs well for months, and I do some updates via apt and every once in a while a reboot is required. Occasionally, one of these reboots kills Pi-Hole, leaving me with the dreaded "Lost connection to API" message. I note that disabling IPv6 in Pihole (in the DHCP settings) allows Pihole to look like it's running but it seems like it doesn't actually respond to any requests from my network, as nothing connects to the internet. When I run ifconfig, my rpi4 no longer has an IPv6 address (just it's IPv4 address). Rebooting does nothing. Using my backup microsd leaves me with the same problem. In the end, I end up having to reinstall everything from scratch, which is a huge waste of time. I recently rebooted my father's Rpi4 (pihole/unbound/wireguard) after updating raspian and that has now gone down. IPv6 connectivity has also disappeared.
Is this a known issue? What causes my rpi4 to lose the ability to work with IPv6? Is it related to PiHole or Wireguard?
Were you able to substantiate that e.g. by running nslookups against Pi-hole's IP addresses when that happened?
I rather suspect it to be another IPv6 configuration issue.
I don't think it's introduced by neither Pi-hole nor Wireguard.
But Wireguard may have triggered it if you had enabled IPv6 forwarding (net.ipv6.conf.<interface>.forwarding) for it, since IPv6 forwarding stops your OS acquring IPv6 RAs.
If that's the case, you may have to reenable IPv6 auto-configuration and RA acquisition by setting the respective entries for net.ipv6.conf.<interface>.autoconf and net.ipv6.conf.<interface>.accept_ra.
However, if you are still using a static IPv6, your network interface should at least still carry that static address, and the above wouldn't apply then.
Hi. I don't configure a static address for the Rpi4, it just keeps it unless I start from scratch. I just cannot figure what suddenly stops the Rpi4 from being able to acquire an IPv6 address at all. I don't know enough about Linux to work out when in the process of booting that this happens. I would have though that this would be an automatic, hardware level process, but it seems software related.