Servidores DNS Principal (mname) y Secundario (rname)
host: daumdn.com
class: IN
ttl: 600
type: SOA
mname: ns.kakaocorp.com
rname: root.kakaocorp.com
serial: 1667970326
refresh: 1800
retry: 600
expire: 2419200
minimum-ttl: 300