Reverse DNS lookup for local hosts not working for IPv6 addresses

Reverse DNS resolution works fine for IPv4, but not for IPv6. I have fd3b:2815:be50::/48 configured as the global IPv6 ULA-prefix and IPv6 itself works completely fine.

IPv4 reverse lookup:

❯ nslookup 192.168.178.65
Server:         192.168.178.1
Address:        192.168.178.1#53

65.178.168.192.in-addr.arpa     name = host.lan.

IPv6 reverse lookup for the same host:

❯ nslookup fd3b:2815:be50:2:14f8:84aa:974d:2681
Server:         192.168.178.1
Address:        192.168.178.1#53

** server can't find 1.8.6.2.d.4.7.9.a.a.4.8.8.f.4.1.2.0.0.0.0.5.e.b.5.1.8.2.b.3.d.f.ip6.arpa: NXDOMAIN

It also doesn't work with the dynamic prefix assigned by my ISP. Is there anything I can do to make this work?

Context: I want to access a PiHole server via IPv6 and IPv4 and PiHole does reverse DNS lookups to show pretty client names in the query log. Right now all IPv6 queries appear with their IP and not their hostname.

Same here. I ran a test on https://ipv6-test.com and got a 19/20 score. Only missing a reverse DNS record for my IPV6 address.

There is no reverse DNS record to associate your IPv6 address with a host name. Reverse DNS records are required by some Internet protocols and are usually managed at the ISP level. Is this only possible for my ISP to fix or can I fix this by myself through OpenWRT?

This should be possible for ULA prefixes:

However, it's problematic for GUA prefixes since it requires:

  • A domain and the proper PTR record - that typically requires money.
  • A static IPv6 - this goes against IPv6 privacy concepts and requires support by the ISP.
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