Pi-hole v6 with Unbound - DNS Resolvers Not Reaching IPv6 Nameservers Despite Active IPv6 Connection

General Discussion
1

Hi,

I’m running Pi-hole v6 and Unbound on my DietPi setup, and both are working perfectly for IPv4. However, I’ve noticed that despite having an active IPv6 connection through my ISP, websites like https://www.dnscheck.tools/ report that my DNS resolvers cannot reach IPv6 nameservers.

Here’s what I’ve checked so far:

  • My router shows IPv6 is enabled and has an active IPv6 address.
  • In dietpi-config, under the network adapter section, IPv6 is enabled.
  • Running ip -6 addr confirms that my eth0 interface has an IPv6 address assigned.

However, when I test connectivity with ping6 -c 4 google.com, I get a “network is unreachable” error.

My question is: how can I configure my setup so that my DNS resolvers (Pi-hole/Unbound) can successfully reach IPv6 nameservers? Any advice or troubleshooting steps would be greatly appreciated!

Thanks!

2

What is the output of:

ip -6 ad ; ip -6 ro list table all; ip -6 ru
nslookup ipv6.google.com

Please make consistent changes in the public IPv6 addresses, for example 2001:1234: can be changed to 20ab:5678: for all.

3

Side note: In principle, IPv6 is not required for DNS resolution itself. IPv6 addresses can also be resolved via IPv4 without any problems

Example, resolve google IPv6 via 9.9.9.9

root@DietPiProd:~# dig google.com AAAA

; <<>> DiG 9.18.33-1~deb12u2-Debian <<>> google.com AAAA
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52021
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;google.com.                    IN      AAAA

;; ANSWER SECTION:
google.com.             28      IN      AAAA    2a00:1450:4001:827::200e

;; Query time: 20 msec
;; SERVER: 9.9.9.9#53(9.9.9.9) (UDP)
;; WHEN: Wed Mar 26 10:58:50 CET 2025
;; MSG SIZE  rcvd: 67

root@DietPiProd:~#