Hello,
That's just a template:
cd /usr/local/directadmin/data/templates
cp named.db custom
cd custom
#edit named.db from the custom directory.
The custom templates take priority. The templates in the "templates" directory get overritten with updates, which is why it's copied.
Also, you can do the same for:
dns_a.conf
dns_cname.conf
dns_mx.conf
dns_ns.conf
I'll update the dns_a.conf to show 127.0.0.1 for the next release.
John