;default soa records
$TTL 38400  ; 10 hours 40 minutes
@       IN SOA  dns dns-admin (
        2021040901 ; serial
        10800      ; refresh (3 hours)
        3600       ; retry (1 hour)
        1209600    ; expire (2 weeks)
        38400      ; minimum (10 hours 40 minutes)
        )