DNS forwarding not working, how to debug?

Hello,

I hope someone can give me a hint for the following problem:

I have installed UCS and imported some users/hosts from a legacy ldap server. Now I got a small hiccup: dns forwarding doesn’t work. I followed this guide and verified my settings as follows:

root@ucs-master:~# ucr search --brief ^nameserv dns/forward
dns/forwarder1: 1.1.1.1
dns/forwarder2: 8.8.8.8
dns/forwarder3: 9.9.9.9
nameserver/external: false
nameserver/option/timeout: 2
nameserver1: 1.2.3.4
nameserver2: <empty>
nameserver3: <empty>

where 1.2.3.4 is the ip of the ucs server. When I test from another server:

dig @1.2.3.4 somehost.mydomain.com

it works (mydomain.com is domain on the ucs server and somehost entry exists)

but

dig @1.2.3.4 google.com

does not (empty response).

I have been pulling my hair for a while now, since I also installed another UCS server in the past using the same procedure, and dns forwarding works fine on that server.

What am I missing, or what can I try to troubleshoot the problem?

Edit: on ucs server the following commands work

dig @1.2.3.4 somehost.mydomain.com
dig @1.2.3.4 google.com
dig somehost.mydomain.com
dig google.com

Edit2: dns/backend is ldap:

root@ucs-master:/etc/bind# ucr search --brief dns/backend
dns/backend: ldap

Regards,
Tony

I found the cause in this post, in case someone hits the same problem.

tl;dr;

ucr get dns/allow/query/cache # get current value
ucr set dns/allow/query/cache="$CURRENT_VALUE; $EXTRA_NET"
service bind9 restart

Regards,
Tony