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