Servidores DNS Principal (mname) y Secundario (rname)
host: sextube.com
class: IN
ttl: 3600
type: SOA
mname: sdns3.ultradns.net
rname: dns.mindgeek.com
serial: 2025111802
refresh: 3600
retry: 3600
expire: 3600
minimum-ttl: 3600