You can have your own root nameserver on your network; and / or your own TLD's; or even do fun stuff where you subvert some names on your net and let "public" a

You can have your own root nameserver on your network; and / or your own TLD's; or even do fun stuff where you subvert some names on your net and let "public" answers through for others. If thats not enough there are a few "alternate roots" systems around still I think: https://icannwiki.org/Alternative_Roots https://icannwiki.org/Alternative_Roots