Master DNS server hostname
By default, Virtualmin will use the system's hostname in the primary NS
and SOA records for new DNS domains it creates. However, if the hostname is not
a valid DNS name or it not suitable for your purposes, this option can
be used to enter a different primary nameserver. It must resolve
to the externally accessible IP address of your system, or the address of
a slave nameserver system for domains created using this template.