$ORIGIN example.com. ; not necessary, using this to self-document $TTL 3600 @ IN SOA ns1.example.com. admin.example.com. ( 1970010100 7200 1800 1209600 300) @ IN NS ns1.example.com. @ IN NS ns2.example.com. @ IN A 198.51.100.1 ns1 IN A 198.51.100.2 ns2 IN A 198.51.100.3 sub1 IN NS...