Help forwarding PTR queries from Unbound to Knot DNS

[April Conger]

Hi all,

I'm setting up Unbound in my home lab and am having trouble forwarding PTR
queries to my Knot DNS server. My A queries for `econger.net` work fine,
but reverse lookups for the 10.0.0.0/24 range appear to follow the normal
recursion path to the root servers, as indicated by my query logs.

Here is my test configuration:

remote-control:
  control-enable: yes
  control-interface: /run/unbound.ctl

server:
  verbosity: 3
  log-servfail: yes
  auto-trust-anchor-file: "/var/lib/unbound/root.key"
  qname-minimisation: yes
  interface: 10.0.0.11
  access-control: 10.0.0.0/16 allow
  private-address: 10.0.0.0/24
  private-domain: econger.net.
  private-domain: 0.0.10.in-addr.arpa.

stub-zone:
  name: "econger.net."
  stub-addr: 10.0.0.14

stub-zone:
  name: "0.0.10.in-addr.arpa."
  stub-addr: 10.0.0.14

While the econger.net stub works fine, the 0.0.10.in-addr.arpa stub does
not. I also tried configuring these as forward-zone entries using
forward-addr, but I got the same result.

Here’s the error I see during reverse lookups:

root at raspy1:/etc/unbound# nslookup 10.0.0.1 10.0.0.11
** server can't find 1.0.0.10.in-addr.arpa: NXDOMAIN

However, querying the same address directly from my Knot DNS server works
fine:

root at raspy1:/etc/unbound# nslookup 10.0.0.1 10.0.0.14
1.0.0.10.in-addr.arpa name = fw1.econger.net.

I'm using Unbound version 1.19.2-1ubuntu3.2 on Ubuntu 24.04.1 on a
Raspberry Pi 3 B+, and Knot DNS version 3.3.4-1.1build2 on the same
hardware/OS combo.

Any advice on what might be wrong or how to resolve the issue would be
greatly appreciated!

Thanks,
April
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.nlnetlabs.nl/pipermail/unbound-users/attachments/20241004/8135f35a/attachment.htm>