Also a good argument for, if you run internal-network only resources, to purchase and use an actual domain for it (such as companyname.us or whatever). Publish

Also a good argument for, if you run internal-network only resources, to purchase and use an actual domain for it (such as companyname.us or whatever). Publish a zone file for the domain as authoritative master and secondary on an internet facing DNS server, but have basically no records in the zone (no useful A or CNAME or anything else). Host the actual DNS for your internal services on your internally-accessible-only DNS server.