$ORIGIN example.
example.      86400  IN  SOA     ns1 admin 2018031900 (
                                 1800 900 604800 86400 )
              86400  IN  NS      ns1
              86400  IN  NS      ns2
              86400  IN  ZONEMD  2018031900 1 1 (
                                 c68090d90a7aed71
                                 6bc459f9340e3d7c
                                 1370d4d24b7e2fc3
                                 a1ddc0b9a87153b9
                                 a9713b3c9ae5cc27
                                 777f98b8e730044c )
ns1           3600   IN  A       203.0.113.63
ns2           3600   IN  AAAA    2001:db8::63