Servidores DNS Principal (mname) y Secundario (rname)
host: preventativemaintanancesvc.com
class: IN
ttl: 21600
type: SOA
mname: edns3.ultradns.com
rname: atsa.coxautoinc.com
serial: 2023042505
refresh: 86400
retry: 86400
expire: 86400
minimum-ttl: 86400