in my infrastructure are some non-ucs Networks. They are using e.g. 192.168.3/24.
I used disable-empty-zone to ignore loading an empty zone, so my forwarders have to be asked:
i am not familiar with this option and what it does, but one problem might be that /etc/bind/named.conf.options is not included in the bind config (named.conf.debian is not used in UCS)
Problem is, this file is automatically generated from a template (triggered by setting certain UCR variables or updates of the univention-bind package) and your changes might be lost.
You could also modify the template /etc/univention/templates/files/etc/bind/named.conf.proxy, but in doing so you loose all further updates of this template (it is a configuration file and we do not overwrite modified configuration files during package updates).
So, i suggest not to edit the template but the file itself, even if that means you have to check the file for your changes after updates.
Please let me know if changing the options in /etc/bind/named.conf.proxy helps you. If so i will create a feature request to allow arbitrary options in /etc/bind/named.conf.proxy via UCR variables (options can be set in UCR variables and the template includes the content of these variables into the options block).